diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
index 826ae72230cf..554f98183fc7 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
@@ -225,6 +225,8 @@ protected enum ENUM_PROPERTY_NAMING_TYPE {MACRO_CASE, legacy, original}
     @Setter
     protected boolean useJspecify;
     protected JSpecifyNullableLambda jSpecifyNullableLambda;
+    protected RemoveAnnotationLambda removeAnnotationLambda;
+
     @Getter @Setter
     protected boolean useDeductionForOneOfInterfaces = false;
 
@@ -706,9 +708,8 @@ public void processOpts() {
             }
             writer.write(content);
         });
-        additionalProperties.put("removeAnnotations", (Mustache.Lambda) (fragment, writer) -> {
-            writer.write(removeAnnotations(fragment.execute()));
-        });
+        this.removeAnnotationLambda = new RemoveAnnotationLambda();
+        additionalProperties.put("removeAnnotations", removeAnnotationLambda);
         additionalProperties.put("sanitizeDataType", (Mustache.Lambda) (fragment, writer) -> {
             writer.write(sanitizeDataType(fragment.execute()));
         });
@@ -881,6 +882,8 @@ protected void applyJspecify() {
                     (sourceFolder + File.separator + apiPackage).replace(".", java.io.File.separator),
                     "package-info.java"));
         }
+        // simplify mustache template for jspecify. @Nullable is kept
+        this.removeAnnotationLambda.keepAnnotation("@Nullable");
     }
 
     @Override
@@ -2076,6 +2079,7 @@ public void postProcessResponseWithProperty(CodegenResponse response, CodegenPro
      * <p>
      * For example:
      * <ul>
+     *     <li>{@code @jakarta.annotation.Nullable String} -> {@code String}</li>
      *     <li>{@code @Min(0) @Max(10)Integer} -> {@code Integer}</li>
      *     <li>{@code @Pattern(regexp = "^[a-z]$")String>} -> {@code String}</li>
      *     <li>{@code List<@Pattern(regexp = "^[a-z]$")String>}" -> "{@code List<String>}"</li>
@@ -2087,7 +2091,38 @@ public void postProcessResponseWithProperty(CodegenResponse response, CodegenPro
      */
     public String removeAnnotations(String dataType) {
         if (dataType != null && dataType.contains("@")) {
-            return dataType.replaceAll("(?:(?i)@[a-z0-9]*+([(].*[)]|\\s*))*+", "");
+            return dataType.replaceAll("(?:(?i)@[a-z0-9\\.]*+([(].*[)]|\\s*))*+", "");
+        }
+        return dataType;
+    }
+
+    /**
+     * Remove annotations from the given data type string except annotationToKeep.
+     * <p>
+     * For example:
+     * <ul>
+     *     <li>{@code @Nullable @Min(0) @Max(10)Integer} -> {@code @Nullable Integer}</li>
+     *     <li>{@code @Nullable List<@Valid Pet>}" -> "{@code @Nullable List<Pet>}"</li>
+     * </ul>
+     *
+     * @param dataType the data type string
+     * @param annotationToKeep annotation to keep. For example @Nullable
+     * @return the data type string without annotations.
+     */
+    public String removeAnnotationsWithExclusion(String dataType, String annotationToKeep) {
+        if (dataType != null && dataType.contains("@")) {
+            if (annotationToKeep == null) {
+                return dataType.replaceAll("(?:(?i)@[a-z0-9\\.]*+([(].*[)]|\\s*))*+", "");
+            }
+            annotationToKeep += " ";
+            boolean annotationPresent = dataType.indexOf(annotationToKeep) >=0;
+            if (annotationPresent) {
+                dataType = dataType.replace( annotationToKeep, "%%");
+            }
+            dataType = dataType.replaceAll("(?:(?i)@[a-z0-9\\.]*+([(].*[)]|\\s*))*+", "");
+            if (annotationPresent) {
+                dataType = dataType.replace("%%", annotationToKeep);
+            }
         }
         return dataType;
     }
@@ -2876,7 +2911,7 @@ private int getLastIndex(String dataType) {
     /**
      * for Jspecify, remove @Nullable before the datatype and set keptNullable to true if done.
      */
-    class JSpecifyNullableLambda implements Mustache.Lambda {
+    protected class JSpecifyNullableLambda implements Mustache.Lambda {
         private String nullableAnnotation = "@Nullable";
         // remember @Nullable annotation value when jspecify is used.
         private String keptNullable = null;
@@ -2926,4 +2961,21 @@ protected void addNullableImportForOperation(CodegenOperation codegenOperation)
                 .findAny()
                 .ifPresent(param -> codegenOperation.imports.add("Nullable"));
     }
+
+    /**
+     * Simplify the removeAnnotations lambda for custom removal.
+     */
+    protected class RemoveAnnotationLambda implements Mustache.Lambda {
+
+        private String keep;
+
+        @Override
+        public void execute(Template.Fragment fragment, Writer writer) throws IOException {
+            writer.write(removeAnnotationsWithExclusion(fragment.execute(), keep));
+        }
+
+        public void keepAnnotation(String keep) {
+            this.keep = keep;
+        }
+    }
 }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
index 4a252d8f796a..6f6cb0af8471 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
@@ -17,6 +17,7 @@
 
 package org.openapitools.codegen.languages;
 
+import com.samskivert.mustache.Mustache;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.servers.Server;
@@ -1411,8 +1412,9 @@ protected void applyJspecify() {
                     (sourceFolder + File.separator + invokerPackage).replace(".", java.io.File.separator),
                     "package-info.java"));
         }
+        String nullableAnnotation = "@" + additionalProperties.get(JAVAX_PACKAGE) + ".annotation.Nullable";
         //  nullable_var_annotations.mustache generates nullable annotations as @{{javaxPackage}}.annotation.Nullable
         // override the default pattern for the "find and replace"
-        jSpecifyNullableLambda.setNullableAnnotation("@" + additionalProperties.get(JAVAX_PACKAGE) + ".annotation.Nullable");
+        jSpecifyNullableLambda.setNullableAnnotation(nullableAnnotation);
     }
 }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/feign/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/feign/pojo.mustache
index 6552166eaecf..dd8bdc7d0371 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/feign/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/feign/pojo.mustache
@@ -125,7 +125,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -148,7 +148,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
index b14cc844cb56..4c6f9bf697e4 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
@@ -135,7 +135,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -158,7 +158,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -209,7 +209,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey3/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey3/pojo.mustache
index b14cc844cb56..4c6f9bf697e4 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey3/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey3/pojo.mustache
@@ -135,7 +135,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -158,7 +158,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -209,7 +209,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
index 36d2f52f0ede..7994cc2d1181 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
@@ -126,7 +126,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -149,7 +149,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -200,7 +200,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pojo.mustache
index 05b7d68369f6..0224febae000 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pojo.mustache
@@ -171,7 +171,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/restclient/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/restclient/pojo.mustache
index d507b60ec467..c720bbd89223 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/restclient/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/restclient/pojo.mustache
@@ -151,7 +151,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -174,7 +174,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -230,7 +230,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pojo.mustache
index 7ec14493ef56..b45c6b5007b1 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pojo.mustache
@@ -151,7 +151,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -174,7 +174,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -230,7 +230,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/webclient/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/webclient/pojo.mustache
index 4ffe46114fa6..95d6986ff4c6 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/webclient/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/webclient/pojo.mustache
@@ -151,7 +151,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -174,7 +174,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -230,7 +230,7 @@ public {{>sealed}}class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#v
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/Java/nullableArgument_builder.mustache b/modules/openapi-generator/src/main/resources/Java/nullableArgument_builder.mustache
index de9d3628ca94..f42c447f5c80 100644
--- a/modules/openapi-generator/src/main/resources/Java/nullableArgument_builder.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/nullableArgument_builder.mustache
@@ -1 +1 @@
-{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{^required}}@{{javaxPackage}}.annotation.Nullable {{/required}}{{/lambda.jSpecifyNullable}}{{#lambda.jSpecifyDatatype}}{{#removeAnnotations}}{{{datatypeWithEnum}}}{{/removeAnnotations}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{#removeAnnotations}}{{{datatypeWithEnum}}}{{/removeAnnotations}}{{/useJspecify}}
\ No newline at end of file
+{{#removeAnnotations}}{{>nullableArgumentWithEnum}}{{/removeAnnotations}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/Java/nullable_var_annotations.mustache b/modules/openapi-generator/src/main/resources/Java/nullable_var_annotations.mustache
index 4f6f6f13dbe1..7b13c89bca91 100644
--- a/modules/openapi-generator/src/main/resources/Java/nullable_var_annotations.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/nullable_var_annotations.mustache
@@ -1 +1 @@
-{{^useJspecify}}{{#required}}{{#isNullable}}@{{javaxPackage}}.annotation.Nullable{{/isNullable}}{{^isNullable}}@{{javaxPackage}}.annotation.Nonnull{{/isNullable}}{{/required}}{{^required}}@{{javaxPackage}}.annotation.Nullable{{/required}}{{/useJspecify}}{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{^required}}@{{javaxPackage}}.annotation.Nullable {{/required}}{{/lambda.jSpecifyNullable}}{{/useJspecify}}
\ No newline at end of file
+{{#lambda.jSpecifyNullable}}{{^useJspecify}}{{#required}}{{#isNullable}}@{{javaxPackage}}.annotation.Nullable{{/isNullable}}{{^isNullable}}@{{javaxPackage}}.annotation.Nonnull{{/isNullable}}{{/required}}{{^required}}@{{javaxPackage}}.annotation.Nullable{{/required}}{{/useJspecify}}{{#useJspecify}}{{#required}}{{#isNullable}}@{{javaxPackage}}.annotation.Nullable {{/isNullable}}{{/required}}{{^required}}@{{javaxPackage}}.annotation.Nullable {{/required}}{{/useJspecify}}{{/lambda.jSpecifyNullable}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/Java/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/pojo.mustache
index 2c1ff7e32cf3..14d2228aa97d 100644
--- a/modules/openapi-generator/src/main/resources/Java/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/pojo.mustache
@@ -154,7 +154,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}});
     }
     try {
@@ -177,7 +177,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#vendorExtensions.x-is-jackson-optional-nullable}}
-    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+    if (this.{{name}} == null || !this.{{name}}.isPresent() || this.{{name}}.get() == null) {
       this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}}{{^defaultValue}}new HashMap<>(){{/defaultValue}});
     }
     try {
@@ -233,7 +233,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}value = "{{{description}}}")
 {{/swagger1AnnotationLibrary}}
 {{#swagger2AnnotationLibrary}}
-  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}")
+  @Schema({{#example}}example = "{{{.}}}", {{/example}}requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}, description = "{{{description}}}"{{#isNullable}}, nullable = true{{/isNullable}})
 {{/swagger2AnnotationLibrary}}
 {{#vendorExtensions.x-extra-annotation}}
   {{{vendorExtensions.x-extra-annotation}}}
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/beanValidation.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/beanValidation.mustache
index 0aed4a92d734..325a13688611 100644
--- a/modules/openapi-generator/src/main/resources/JavaSpring/beanValidation.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/beanValidation.mustache
@@ -1 +1 @@
-{{#required}}{{^isReadOnly}}@NotNull {{/isReadOnly}}{{/required}}{{#isContainer}}{{^isPrimitiveType}}{{^isEnum}}@Valid {{/isEnum}}{{/isPrimitiveType}}{{/isContainer}}{{^isContainer}}{{^isPrimitiveType}}@Valid {{/isPrimitiveType}}{{/isContainer}}{{^openApiNullable}}{{>beanValidationCore}}{{/openApiNullable}}{{#openApiNullable}}{{^useOptional}}{{>beanValidationCore}}{{/useOptional}}{{/openApiNullable}}{{#useOptional}}{{#openApiNullable}}{{#isContainer}}{{^required}}{{>beanValidationCore}}{{/required}}{{/isContainer}}{{/openApiNullable}}{{#openApiNullable}}{{#required}}{{>beanValidationCore}}{{/required}}{{/openApiNullable}}{{/useOptional}}
\ No newline at end of file
+{{>notNull}}{{#isContainer}}{{^isPrimitiveType}}{{^isEnum}}@Valid {{/isEnum}}{{/isPrimitiveType}}{{/isContainer}}{{^isContainer}}{{^isPrimitiveType}}@Valid {{/isPrimitiveType}}{{/isContainer}}{{^openApiNullable}}{{>beanValidationCore}}{{/openApiNullable}}{{#openApiNullable}}{{^useOptional}}{{>beanValidationCore}}{{/useOptional}}{{/openApiNullable}}{{#useOptional}}{{#openApiNullable}}{{#isContainer}}{{^required}}{{>beanValidationCore}}{{/required}}{{/isContainer}}{{/openApiNullable}}{{#openApiNullable}}{{#required}}{{>beanValidationCore}}{{/required}}{{/openApiNullable}}{{/useOptional}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/notNull.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/notNull.mustache
new file mode 100644
index 000000000000..590235a968a5
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/notNull.mustache
@@ -0,0 +1 @@
+{{#required}}{{^isReadOnly}}{{#isNullable}}{{#openApiNullable}}/* @Present */ {{/openApiNullable}}{{/isNullable}}{{^isNullable}}@NotNull {{/isNullable}}{{/isReadOnly}}{{/required}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/nullableAnnotation_jspecify.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/nullableAnnotation_jspecify.mustache
index 225d7f0ff62c..c7624e180091 100644
--- a/modules/openapi-generator/src/main/resources/JavaSpring/nullableAnnotation_jspecify.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/nullableAnnotation_jspecify.mustache
@@ -1 +1 @@
-{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{^required}}{{^useOptional}}{{#openApiNullable}}{{^isNullable}}@Nullable {{/isNullable}}{{/openApiNullable}}{{^openApiNullable}}@Nullable {{/openApiNullable}}{{/useOptional}}{{/required}}{{/lambda.jSpecifyNullable}}{{/useJspecify}}
\ No newline at end of file
+{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{#required}}{{#isNullable}}{{^openApiNullable}}@Nullable {{/openApiNullable}}{{/isNullable}}{{/required}}{{^required}}{{^useOptional}}{{#openApiNullable}}{{^isNullable}}@Nullable {{/isNullable}}{{/openApiNullable}}{{^openApiNullable}}@Nullable {{/openApiNullable}}{{/useOptional}}{{/required}}{{/lambda.jSpecifyNullable}}{{/useJspecify}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_builder.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_builder.mustache
index e42e412e8730..4327e45d9e2a 100644
--- a/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_builder.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_builder.mustache
@@ -1 +1 @@
-{{#useJspecify}}{{^required}}{{#lambda.jSpecifyNullable}}{{^useOptional}}@Nullable {{/useOptional}}{{#useOptional}}{{#optionalAcceptNullable}}@Nullable {{/optionalAcceptNullable}}{{/useOptional}}{{/lambda.jSpecifyNullable}}{{/required}}{{#lambda.jSpecifyDatatype}}{{#removeAnnotations}}{{{datatypeWithEnum}}}{{/removeAnnotations}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{#removeAnnotations}}{{{datatypeWithEnum}}}{{/removeAnnotations}}{{/useJspecify}}
\ No newline at end of file
+{{#removeAnnotations}}{{>nullableArgument_chainSetter}}{{/removeAnnotations}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_chainSetter.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_chainSetter.mustache
new file mode 100644
index 000000000000..a199e52ba86c
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_chainSetter.mustache
@@ -0,0 +1 @@
+{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{#required}}{{#isNullable}}@Nullable {{/isNullable}}{{/required}}{{^required}}{{^useOptional}}@Nullable {{/useOptional}}{{#useOptional}}{{#optionalAcceptNullable}}@Nullable {{/optionalAcceptNullable}}{{/useOptional}}{{/required}}{{/lambda.jSpecifyNullable}}{{#lambda.jSpecifyDatatype}}{{{datatypeWithEnum}}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{>nullableAnnotation_default}}{{{datatypeWithEnum}}}{{/useJspecify}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_constructor.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_constructor.mustache
new file mode 100644
index 000000000000..a001ec18760d
--- /dev/null
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/nullableArgument_constructor.mustache
@@ -0,0 +1 @@
+{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{#required}}{{#isNullable}}@Nullable {{/isNullable}}{{/required}}{{^required}}@Nullable {{/required}}{{/lambda.jSpecifyNullable}}{{#lambda.jSpecifyDatatype}}{{{datatypeWithEnum}}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{>nullableAnnotation}}{{{datatypeWithEnum}}}{{/useJspecify}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/JavaSpring/pojo.mustache b/modules/openapi-generator/src/main/resources/JavaSpring/pojo.mustache
index 47b1fd30dae0..99dc720a635d 100644
--- a/modules/openapi-generator/src/main/resources/JavaSpring/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/JavaSpring/pojo.mustache
@@ -112,7 +112,7 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
   /**
    * Constructor with only required parameters{{#generateConstructorWithAllArgs}}{{^vendorExtensions.x-java-all-args-constructor}} and all parameters{{/vendorExtensions.x-java-all-args-constructor}}{{/generateConstructorWithAllArgs}}
    */
-  public {{classname}}({{#requiredVars}}{{{datatypeWithEnum}}} {{name}}{{^-last}}, {{/-last}}{{/requiredVars}}) {
+  public {{classname}}({{#requiredVars}}{{>nullableArgument_constructor}} {{name}}{{^-last}}, {{/-last}}{{/requiredVars}}) {
     {{#parent}}
     super({{#parentRequiredVars}}{{name}}{{^-last}}, {{/-last}}{{/parentRequiredVars}});
     {{/parent}}
@@ -135,7 +135,7 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
   /**
    * Constructor with all args parameters
    */
-  public {{classname}}({{#vendorExtensions.x-java-all-args-constructor-vars}}{{#useJspecify}}{{#lambda.jSpecifyNullable}}{{^required}}@Nullable {{/required}}{{/lambda.jSpecifyNullable}}{{#lambda.jSpecifyDatatype}}{{{datatypeWithEnum}}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{>nullableAnnotation}}{{{datatypeWithEnum}}}{{/useJspecify}} {{name}}{{^-last}}, {{/-last}}{{/vendorExtensions.x-java-all-args-constructor-vars}}) {
+  public {{classname}}({{#vendorExtensions.x-java-all-args-constructor-vars}}{{>nullableArgument_constructor}} {{name}}{{^-last}}, {{/-last}}{{/vendorExtensions.x-java-all-args-constructor-vars}}) {
   {{#parent}}
       super({{#parentVars}}{{name}}{{^-last}}, {{/-last}}{{/parentVars}});
   {{/parent}}
@@ -154,7 +154,7 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
   {{^lombok.Data}}
 
   {{! begin feature: fluent setter methods }}
-  public {{classname}} {{name}}({{#useJspecify}}{{#lambda.jSpecifyNullable}}{{^required}}{{^useOptional}}@Nullable {{/useOptional}}{{#useOptional}}{{#optionalAcceptNullable}}@Nullable {{/optionalAcceptNullable}}{{/useOptional}}{{/required}}{{/lambda.jSpecifyNullable}}{{#lambda.jSpecifyDatatype}}{{{datatypeWithEnum}}}{{/lambda.jSpecifyDatatype}}{{/useJspecify}}{{^useJspecify}}{{>nullableAnnotation_default}}{{{datatypeWithEnum}}}{{/useJspecify}} {{name}}) {
+  public {{classname}} {{name}}({{>nullableArgument_chainSetter}} {{name}}) {
     {{#openApiNullable}}
     this.{{name}} = {{#isNullable}}JsonNullable.of({{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}Optional.of{{#optionalAcceptNullable}}Nullable{{/optionalAcceptNullable}}({{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}}{{name}}{{#isNullable}}){{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}){{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}};
     {{/openApiNullable}}
@@ -167,7 +167,7 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
 
   public {{classname}} add{{nameInPascalCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#openApiNullable}}
-    if (this.{{name}} == null{{#isNullable}} || !this.{{name}}.isPresent(){{/isNullable}}) {
+    if (this.{{name}} == null{{#isNullable}} || !this.{{name}}.isPresent() || this.{{name}}.get() == null{{/isNullable}}) {
       this.{{name}} = {{#isNullable}}JsonNullable.of({{/isNullable}}{{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}ArrayList{{/uniqueItems}}<>(){{/defaultValue}}{{#isNullable}}){{/isNullable}};
     }
     this.{{name}}{{#isNullable}}.get(){{/isNullable}}.add({{name}}Item);
@@ -185,7 +185,7 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
 
   public {{classname}} put{{nameInPascalCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
     {{#openApiNullable}}
-    if (this.{{name}} == null{{#isNullable}} || !this.{{name}}.isPresent(){{/isNullable}}) {
+    if (this.{{name}} == null{{#isNullable}} || !this.{{name}}.isPresent() || this.{{name}}.get() == null{{/isNullable}}) {
       this.{{name}} = {{#isNullable}}JsonNullable.of({{/isNullable}}{{{defaultValue}}}{{^defaultValue}}new {{#uniqueItems}}LinkedHashSet{{/uniqueItems}}{{^uniqueItems}}HashMap{{/uniqueItems}}<>(){{/defaultValue}}{{#isNullable}}){{/isNullable}};
     }
     this.{{name}}{{#isNullable}}.get(){{/isNullable}}.put(key, {{name}}Item);
@@ -228,10 +228,10 @@ public {{>sealed}}class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}
   {{>beanValidation}}{{! prevent indent}}
   {{/useBeanValidation}}
   {{^useBeanValidation}}
-  {{#required}}@NotNull{{/required}}
+  {{#lambda.trim}}{{>notNull}}{{/lambda.trim}}
   {{/useBeanValidation}}
   {{#swagger2AnnotationLibrary}}
-  @Schema(name = "{{{baseName}}}"{{#isReadOnly}}, accessMode = Schema.AccessMode.READ_ONLY{{/isReadOnly}}{{#example}}, example = "{{{.}}}"{{/example}}{{#description}}, description = "{{{.}}}"{{/description}}{{#deprecated}}, deprecated = true{{/deprecated}}, requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}})
+  @Schema(name = "{{{baseName}}}"{{#isReadOnly}}, accessMode = Schema.AccessMode.READ_ONLY{{/isReadOnly}}{{#example}}, example = "{{{.}}}"{{/example}}{{#description}}, description = "{{{.}}}"{{/description}}{{#deprecated}}, deprecated = true{{/deprecated}}, requiredMode = {{#required}}Schema.RequiredMode.REQUIRED{{/required}}{{^required}}Schema.RequiredMode.NOT_REQUIRED{{/required}}{{#isNullable}}, nullable = true{{/isNullable}})
   {{/swagger2AnnotationLibrary}}
   {{#swagger1AnnotationLibrary}}
   @ApiModelProperty({{#example}}example = "{{{.}}}", {{/example}}{{#required}}required = {{required}}, {{/required}}{{#isReadOnly}}readOnly = {{{isReadOnly}}}, {{/isReadOnly}}value = "{{{description}}}")
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java
index bd2a9ed544c9..b3940c9078ba 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java
@@ -4697,27 +4697,28 @@ public void testRestClientMultipartFormParamsGuardAgainstEmptyLists() {
     @DataProvider(name = "jspecifyLibraries")
     public Object[][] jspecifyLibraries() {
         return new Object[][]{
-                {"restclient", false, true},
-                {"restclient", true, false},
-                {"webclient", false, true},
-                {"webclient", true, false},
-                {"resttemplate", false, true},
-                {"resttemplate", true, true},
-                {"native", false, true}
+                {"restclient", 3, true},
+                {"restclient", 4, false},
+                {"webclient", 3, true},
+                {"webclient", 4, false},
+                {"resttemplate", 3, true},
+                {"resttemplate", 4, true},
+                {"native", 3, true}
         };
     }
 
     @Test(dataProvider = "jspecifyLibraries")
-    public void testJspecify(String library, boolean useSpringBoot4, boolean hasJspecifyDependency) throws IOException {
+    public void testJspecify(String library, int springBootVersion, boolean hasJspecifyDependency) throws IOException {
         final Map<String, File> files = generateFromContract("src/test/resources/3_0/java/jspecify.yaml", library,
                 Map.of(USE_JSPECIFY, true,
                         "containerDefaultToNull", true,
-                        USE_SPRING_BOOT4, useSpringBoot4,
+                        USE_SPRING_BOOT4, springBootVersion == 4,
                         JavaClientCodegen.OPENAPI_NULLABLE, false,
                         GENERATE_CONSTRUCTOR_WITH_ALL_ARGS, true,
                         GENERATE_BUILDERS, true,
-                        USE_ABSTRACTION_FOR_FILES, true
-                ),
+                        USE_ABSTRACTION_FOR_FILES, true,
+                        ANNOTATION_LIBRARY, "swagger2"
+                        ),
                 codegenConfigurator ->
                         codegenConfigurator
                                 .setValidateSpec(false)
@@ -4760,6 +4761,16 @@ public void testJspecify(String library, boolean useSpringBoot4, boolean hasJspe
                     .fileContains(
                         "public Foo(@JsonProperty(JSON_PROPERTY_DT) java.time.@Nullable Instant dt, @JsonProperty(JSON_PROPERTY_NULLABLE_DT) java.time.@Nullable Instant nullableDt, @JsonProperty(JSON_PROPERTY_BINARY) @Nullable File binary, @JsonProperty(JSON_PROPERTY_NULLABLE_BINARY) @Nullable File nullableBinary, @JsonProperty(JSON_PROPERTY_LIST_OF_DT) @Nullable List<java.time.Instant> listOfDt, @JsonProperty(JSON_PROPERTY_LIST_MIN_INTEMS) @Nullable List<java.time.Instant> listMinIntems, @JsonProperty(JSON_PROPERTY_NULLABLE_LIST_MIN_INTEMS) @Nullable List<java.time.Instant> nullableListMinIntems, @JsonProperty(JSON_PROPERTY_REQUIRED_DT) java.time.Instant requiredDt, @JsonProperty(JSON_PROPERTY_NUMBER) java.math.@Nullable BigDecimal number, @JsonProperty(JSON_PROPERTY_NULLABLE_NUMBER) java.math.@Nullable BigDecimal nullableNumber, @JsonProperty(JSON_PROPERTY_COLOR) @Nullable String color, @JsonProperty(JSON_PROPERTY_REQUIRED_COLOR) String requiredColor, @JsonProperty(JSON_PROPERTY_NULLABLE_COLOR) @Nullable String nullableColor) {");
         }
+        JavaFileAssert.assertThat(files.get("RequiredAndNullable.java"))
+                .fileContains(
+                        "void setStr(@Nullable String str)",
+                        "RequiredAndNullable str(@Nullable String str)",
+                        "@Schema(requiredMode = Schema.RequiredMode.REQUIRED, description = \"\", nullable = true)");
+        JavaFileAssert.assertThat(files.get("FileContent.java"))
+                .fileContains(
+                        "private @Nullable VirusScanEnum virusScan",
+                        "FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan)"
+                );
         if (!RESTTEMPLATE.equals(library)) {
             JavaFileAssert.assertThat(files.get("FooApi.java"))
                     .fileContains("fooDtParamGet(java.time.@Nullable Instant dtParam, java.time.@Nullable Instant dtQuery, java.time.@Nullable Instant dtCookie, @Nullable String color)");
@@ -4778,14 +4789,15 @@ public void testJspecify(String library, boolean useSpringBoot4, boolean hasJspe
     }
 
     @Test(dataProvider = "jspecifyLibraries")
-    public void testJspecify_openapiNullable(String library, boolean useSpringBoot4, boolean hasJspecifyDependency) throws IOException {
+    public void testJspecify_openapiNullable(String library, int springBootVersion, boolean hasJspecifyDependency) throws IOException {
         final Map<String, File> files = generateFromContract("src/test/resources/3_0/java/jspecify.yaml", library,
                 Map.of(USE_JSPECIFY, true,
                         "containerDefaultToNull", true,
-                        USE_SPRING_BOOT4, useSpringBoot4,
+                        USE_SPRING_BOOT4, springBootVersion == 4,
                         JavaClientCodegen.OPENAPI_NULLABLE, true,
                         GENERATE_CONSTRUCTOR_WITH_ALL_ARGS, true,
-                        GENERATE_BUILDERS, true
+                        GENERATE_BUILDERS, true,
+                        ANNOTATION_LIBRARY, "swagger2"
                 ),
                 codegenConfigurator ->
                         codegenConfigurator
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java
index e5c1ad926aa6..d959fdcb607a 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java
@@ -7143,6 +7143,7 @@ public void testJspecify(String library, int springBootVersion) throws IOExcepti
                         SpringCodegen.OPENAPI_NULLABLE, false,
                         USE_BEANVALIDATION, true,
                         GENERATE_CONSTRUCTOR_WITH_ALL_ARGS, true,
+                        GENERATE_CONSTRUCTOR_WITH_REQUIRED_ARGS, true,
                         INTERFACE_ONLY, false,
                         GENERATE_BUILDERS, true,
                         springVersionProperty, springBootVersion > 2
@@ -7179,7 +7180,10 @@ public void testJspecify(String library, int springBootVersion) throws IOExcepti
                         "Foo.Builder dt(java.time.@Nullable Instant dt)",
                         "Foo.Builder requiredDt(java.time.Instant requiredDt)",
                         "Foo.Builder nullableNumber(@Nullable BigDecimal nullableNumber)"
-                );
+                ).fileDoesNotContain(
+                        "javax.annotation.Nullable",
+                        "jakarta.annotation.Nullable")
+                .assertMethod("getRequiredDt").assertMethodAnnotations().containsWithName("NotNull").containsWithName("Valid");
         JavaFileAssert.assertThat(files.get("FooApi.java"))
                 .assertTypeAnnotations().doesImportAnnotation("org.jspecify.annotations.Nullable").toType()
                 .fileContains(
@@ -7188,6 +7192,25 @@ public void testJspecify(String library, int springBootVersion) throws IOExcepti
                         "java.time.@Nullable Instant dtCookie",
                         " @RequestParam(value = \"color\", required = false, defaultValue = \"red\") String color"
                 );
+        JavaFileAssert.assertThat(files.get("RequiredAndNullable.java"))
+                .fileContains(
+                        "private @Nullable String str = null;",
+                        "private @Nullable List<String> _list;",
+                        "RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list)",
+                        "@Nullable String getStr()",
+                        "void setStr(@Nullable String str)",
+                        "RequiredAndNullable str(@Nullable String str)",
+                        "RequiredAndNullable.Builder str(@Nullable String str)"
+                )
+                .assertMethod("getStr").assertMethodAnnotations().doesNotContainWithName("NotNull");
+        if (!library.equals(SPRING_HTTP_INTERFACE)) {
+            // SPRING_HTTP_INTERFACE does not support @Schema generation (yet)
+            JavaFileAssert.assertThat(files.get("RequiredAndNullable.java"))
+                    .fileContains(
+                            "@Schema(name = \"str\", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)");
+        }
+        JavaFileAssert.assertThat(files.get("FileContent.java"))
+                .fileContains("VirusScanEnum getVirusScan()");
         JavaFileAssert.assertThat(files.get("api/package-info.java"))
                 .fileContains("@org.jspecify.annotations.NullMarked");
         JavaFileAssert.assertThat(files.get("model/package-info.java"))
@@ -7210,6 +7233,7 @@ public void testJspecify_openapiNullable(String library, int springBootVersion)
                         CONTAINER_DEFAULT_TO_NULL, true,
                         USE_BEANVALIDATION, true,
                         GENERATE_CONSTRUCTOR_WITH_ALL_ARGS, true,
+                        GENERATE_CONSTRUCTOR_WITH_REQUIRED_ARGS, true,
                         CodegenConstants.OPENAPI_NULLABLE, true,
                         INTERFACE_ONLY, false,
                         GENERATE_BUILDERS, true,
@@ -7246,7 +7270,10 @@ public void testJspecify_openapiNullable(String library, int springBootVersion)
                         "Foo.Builder requiredDt(java.time.Instant requiredDt)",
                         "Foo.Builder nullableNumber(@Nullable BigDecimal nullableNumber)",
                         "Foo.Builder nullableNumber(JsonNullable<BigDecimal> nullableNumber)"
-                );
+                ).fileDoesNotContain(
+                        "javax.annotation.Nullable",
+                        "jakarta.annotation.Nullable")
+                .assertMethod("getRequiredDt").assertMethodAnnotations().containsWithName("NotNull").containsWithName("Valid");
         JavaFileAssert.assertThat(files.get("FooApi.java"))
                 .assertTypeAnnotations().doesImportAnnotation("org.jspecify.annotations.Nullable").toType()
                 .fileContains(
@@ -7254,6 +7281,17 @@ public void testJspecify_openapiNullable(String library, int springBootVersion)
                         "java.time.@Nullable Instant dtQuery",
                         "java.time.@Nullable Instant dtCookie"
                 );
+        JavaFileAssert.assertThat(files.get("RequiredAndNullable.java"))
+                .fileContains(
+                        "private JsonNullable<String> str = JsonNullable.<String>undefined();",
+                        "private JsonNullable<List<String>> _list = JsonNullable.<List<String>>undefined();",
+                        "RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list)",
+                        "JsonNullable<String> getStr()",
+                        "void setStr(JsonNullable<String> str)",
+                        "RequiredAndNullable str(@Nullable String str)",
+                        "RequiredAndNullable.Builder str(@Nullable String str)",
+                        " /* @Present */"
+                ).assertMethod("getStr").assertMethodAnnotations().doesNotContainWithName("NotNull");
         JavaFileAssert.assertThat(files.get("api/package-info.java"))
                 .fileContains("@org.jspecify.annotations.NullMarked");
         JavaFileAssert.assertThat(files.get("model/package-info.java"))
@@ -7287,6 +7325,7 @@ public void testJspecify_useOptional(String library, int springBootVersion, bool
                         CONTAINER_DEFAULT_TO_NULL, true,
                         USE_BEANVALIDATION, true,
                         GENERATE_CONSTRUCTOR_WITH_ALL_ARGS, true,
+                        GENERATE_CONSTRUCTOR_WITH_REQUIRED_ARGS, true,
                         SpringCodegen.USE_OPTIONAL, true,
                         OPTIONAL_ACCEPT_NULLABLE, optionalAcceptNullable,
                         INTERFACE_ONLY, false,
@@ -7319,7 +7358,10 @@ public void testJspecify_useOptional(String library, int springBootVersion, bool
                         "public Foo(java.time.@Nullable Instant dt, java.time.@Nullable Instant nullableDt, org.springframework.core.io.@Nullable Resource binary, org.springframework.core.io.@Nullable Resource nullableBinary, @Nullable List<java.time.Instant> listOfDt, @Nullable List<java.time.Instant> listMinIntems, @Nullable List<java.time.Instant> nullableListMinIntems, java.time.Instant requiredDt, @Nullable BigDecimal number, @Nullable BigDecimal nullableNumber, @Nullable String color, String requiredColor, @Nullable String nullableColor) {",
                         "Foo.Builder requiredDt(java.time.Instant requiredDt)",
                         "Foo.Builder nullableNumber(JsonNullable<BigDecimal> nullableNumber)"
-                );
+                ).fileDoesNotContain(
+                        "javax.annotation.Nullable",
+                        "jakarta.annotation.Nullable")
+                .assertMethod("getRequiredDt").assertMethodAnnotations().containsWithName("NotNull").containsWithName("Valid");
         if (optionalAcceptNullable) {
             fooAssert.fileContains(
                     "Foo dt(java.time.@Nullable Instant dt) {\n    this.dt = Optional.ofNullable(dt);",
@@ -7336,6 +7378,15 @@ public void testJspecify_useOptional(String library, int springBootVersion, bool
                         "Optional<java.time.Instant> dtQuery",
                         "Optional<java.time.Instant> dtCookie"
                 );
+        JavaFileAssert.assertThat(files.get("RequiredAndNullable.java"))
+                .fileContains(
+                        "private JsonNullable<String> str = JsonNullable.<String>undefined();",
+                        "RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list)",
+                        "JsonNullable<String> getStr()",
+                        "void setStr(JsonNullable<String> str)",
+                        "RequiredAndNullable str(@Nullable String str)",
+                        "RequiredAndNullable.Builder str(@Nullable String str)"
+                ).assertMethod("getStr").assertMethodAnnotations().doesNotContainWithName("NotNull");
         JavaFileAssert.assertThat(files.get("api/package-info.java"))
                 .fileContains("@org.jspecify.annotations.NullMarked");
         JavaFileAssert.assertThat(files.get("model/package-info.java"))
diff --git a/modules/openapi-generator/src/test/resources/3_0/java/jspecify.yaml b/modules/openapi-generator/src/test/resources/3_0/java/jspecify.yaml
index 99a4de1af48c..4d166384f1ad 100644
--- a/modules/openapi-generator/src/test/resources/3_0/java/jspecify.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/java/jspecify.yaml
@@ -4,6 +4,8 @@ info:
   title: jspecify
   version: 1.0.0
 tags:
+  - name: requiredAndNullable
+    description: requiredAndNullable
   - name: foo
     description: foo
   - name: upload
@@ -45,6 +47,24 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/Foo'
+  /requiredAndNullable:
+    post:
+      tags:
+        - requiredAndNullable
+      requestBody:
+        required: true
+        description: bodyWithRequiredAndNullableAttributes
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/RequiredAndNullable'
+      responses:
+        default:
+          description: response
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RequiredAndNullable'
   /upload:
     post:
       tags:
@@ -94,7 +114,10 @@ paths:
       responses:
         '200':
           description: ok
- 
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/FileContent'
 components:
   schemas:
     Foo:
@@ -152,7 +175,48 @@ components:
           type: string
           default: red
           nullable: true
-
-
-
-
+    RequiredAndNullable:
+      type: object
+      required:
+        - str
+        - file
+        - color
+        - onlyRequired
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          nullable: true
+          type: string
+          format: binary
+        color:
+          type: string
+          default: red
+          nullable: true
+        onlyRequired:
+          # NON nullable
+          type: string
+        list:
+          type: array
+          nullable: true
+          items:
+            type: string
+    FileContent:
+      type: object
+      required:
+        - name
+      properties:
+        name:
+          type: string
+          readOnly: true
+        size:
+          type: integer
+          readOnly: true
+        virusScan:
+          type: string
+          readOnly: true
+          enum:
+            - clean
+            - detected
diff --git a/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/model/DefaultValue.java
index f1bde487d331..9187ba549dbc 100644
--- a/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -293,7 +293,7 @@ public DefaultValue arrayStringNullable(@javax.annotation.Nullable List<String>
   }
 
   public DefaultValue addArrayStringNullableItem(String arrayStringNullableItem) {
-    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent()) {
+    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent() || this.arrayStringNullable.get() == null) {
       this.arrayStringNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
@@ -338,7 +338,7 @@ public DefaultValue arrayStringExtensionNullable(@javax.annotation.Nullable List
   }
 
   public DefaultValue addArrayStringExtensionNullableItem(String arrayStringExtensionNullableItem) {
-    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent()) {
+    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent() || this.arrayStringExtensionNullable.get() == null) {
       this.arrayStringExtensionNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
index 3ef093b628b3..785dfa821858 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -286,7 +286,7 @@ public DefaultValue arrayStringNullable(@javax.annotation.Nullable List<String>
   }
 
   public DefaultValue addArrayStringNullableItem(String arrayStringNullableItem) {
-    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent()) {
+    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent() || this.arrayStringNullable.get() == null) {
       this.arrayStringNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
@@ -330,7 +330,7 @@ public DefaultValue arrayStringExtensionNullable(@javax.annotation.Nullable List
   }
 
   public DefaultValue addArrayStringExtensionNullableItem(String arrayStringExtensionNullableItem) {
-    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent()) {
+    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent() || this.arrayStringExtensionNullable.get() == null) {
       this.arrayStringExtensionNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/model/DefaultValue.java
index a9d8e94e3ef7..73a13cf4bb17 100644
--- a/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -291,7 +291,7 @@ public DefaultValue arrayStringNullable(@jakarta.annotation.Nullable List<String
   }
 
   public DefaultValue addArrayStringNullableItem(String arrayStringNullableItem) {
-    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent()) {
+    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent() || this.arrayStringNullable.get() == null) {
       this.arrayStringNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
@@ -336,7 +336,7 @@ public DefaultValue arrayStringExtensionNullable(@jakarta.annotation.Nullable Li
   }
 
   public DefaultValue addArrayStringExtensionNullableItem(String arrayStringExtensionNullableItem) {
-    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent()) {
+    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent() || this.arrayStringExtensionNullable.get() == null) {
       this.arrayStringExtensionNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/echo_api/java/resteasy/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/resteasy/src/main/java/org/openapitools/client/model/DefaultValue.java
index af5ff83400cc..a39e748782ad 100644
--- a/samples/client/echo_api/java/resteasy/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/resteasy/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -290,7 +290,7 @@ public DefaultValue arrayStringNullable(@javax.annotation.Nullable List<String>
   }
 
   public DefaultValue addArrayStringNullableItem(String arrayStringNullableItem) {
-    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent()) {
+    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent() || this.arrayStringNullable.get() == null) {
       this.arrayStringNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
@@ -335,7 +335,7 @@ public DefaultValue arrayStringExtensionNullable(@javax.annotation.Nullable List
   }
 
   public DefaultValue addArrayStringExtensionNullableItem(String arrayStringExtensionNullableItem) {
-    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent()) {
+    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent() || this.arrayStringExtensionNullable.get() == null) {
       this.arrayStringExtensionNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/echo_api/java/resttemplate/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/resttemplate/src/main/java/org/openapitools/client/model/DefaultValue.java
index a25c25ef60fe..1cd4856963c5 100644
--- a/samples/client/echo_api/java/resttemplate/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/resttemplate/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -291,7 +291,7 @@ public DefaultValue arrayStringNullable(@javax.annotation.Nullable List<String>
   }
 
   public DefaultValue addArrayStringNullableItem(String arrayStringNullableItem) {
-    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent()) {
+    if (this.arrayStringNullable == null || !this.arrayStringNullable.isPresent() || this.arrayStringNullable.get() == null) {
       this.arrayStringNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
@@ -336,7 +336,7 @@ public DefaultValue arrayStringExtensionNullable(@javax.annotation.Nullable List
   }
 
   public DefaultValue addArrayStringExtensionNullableItem(String arrayStringExtensionNullableItem) {
-    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent()) {
+    if (this.arrayStringExtensionNullable == null || !this.arrayStringExtensionNullable.isPresent() || this.arrayStringExtensionNullable.get() == null) {
       this.arrayStringExtensionNullable = JsonNullable.<List<String>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/petstore/java/apache-httpclient-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/apache-httpclient-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
index 7fc9fa102da5..ef4b78a8f79a 100644
--- a/samples/client/petstore/java/apache-httpclient-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/apache-httpclient-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -319,7 +319,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -364,7 +364,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -442,7 +442,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -487,7 +487,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/model/NullableClass.java
index 9d6883690dee..0a4f4ab52ae5 100644
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -320,7 +320,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -365,7 +365,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -443,7 +443,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -488,7 +488,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/feign-hc5/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/feign-hc5/src/main/java/org/openapitools/client/model/NullableClass.java
index 7b7b56d9ba9d..dd85b49235bd 100644
--- a/samples/client/petstore/java/feign-hc5/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/feign-hc5/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -310,7 +310,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -356,7 +356,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -436,7 +436,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -482,7 +482,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/NullableClass.java
index 7b7b56d9ba9d..dd85b49235bd 100644
--- a/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -310,7 +310,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -356,7 +356,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -436,7 +436,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -482,7 +482,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/jersey3-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/jersey3-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
index e6fb45eef3ec..c0da02d667fa 100644
--- a/samples/client/petstore/java/jersey3-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/jersey3-jackson3/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -363,7 +363,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -443,7 +443,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -489,7 +489,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/NullableClass.java
index 16526b1f6127..4152edc03094 100644
--- a/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/jersey3/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -318,7 +318,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -364,7 +364,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -444,7 +444,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -490,7 +490,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
index b85b8b99e0d5..96a4e9964643 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -302,7 +302,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -346,7 +346,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -422,7 +422,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -466,7 +466,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/.openapi-generator/FILES b/samples/client/petstore/java/native-jackson3-jspecify/.openapi-generator/FILES
index b6ae45415018..b169aa1ef064 100644
--- a/samples/client/petstore/java/native-jackson3-jspecify/.openapi-generator/FILES
+++ b/samples/client/petstore/java/native-jackson3-jspecify/.openapi-generator/FILES
@@ -6,8 +6,11 @@ api/openapi.yaml
 build.gradle
 build.sbt
 docs/FileApi.md
+docs/FileContent.md
 docs/Foo.md
 docs/FooApi.md
+docs/RequiredAndNullable.md
+docs/RequiredAndNullableApi.md
 docs/UploadApi.md
 git_push.sh
 gradle.properties
@@ -31,9 +34,12 @@ src/main/java/org/openapitools/client/ServerConfiguration.java
 src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/api/FileApi.java
 src/main/java/org/openapitools/client/api/FooApi.java
+src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/client/api/UploadApi.java
 src/main/java/org/openapitools/client/api/package-info.java
 src/main/java/org/openapitools/client/model/AbstractOpenApiSchema.java
+src/main/java/org/openapitools/client/model/FileContent.java
 src/main/java/org/openapitools/client/model/Foo.java
+src/main/java/org/openapitools/client/model/RequiredAndNullable.java
 src/main/java/org/openapitools/client/model/package-info.java
 src/main/java/org/openapitools/client/package-info.java
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/README.md b/samples/client/petstore/java/native-jackson3-jspecify/README.md
index 9692175454f4..ae7c8bb3bead 100644
--- a/samples/client/petstore/java/native-jackson3-jspecify/README.md
+++ b/samples/client/petstore/java/native-jackson3-jspecify/README.md
@@ -87,7 +87,8 @@ public class FileApiExample {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -110,6 +111,8 @@ Class | Method | HTTP request | Description
 *FileApi* | [**fileIdGetWithHttpInfo**](docs/FileApi.md#fileIdGetWithHttpInfo) | **GET** /file/{id} | 
 *FooApi* | [**fooDtParamGet**](docs/FooApi.md#fooDtParamGet) | **GET** /foo/{dtParam} | 
 *FooApi* | [**fooDtParamGetWithHttpInfo**](docs/FooApi.md#fooDtParamGetWithHttpInfo) | **GET** /foo/{dtParam} | 
+*RequiredAndNullableApi* | [**requiredAndNullablePost**](docs/RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable | 
+*RequiredAndNullableApi* | [**requiredAndNullablePostWithHttpInfo**](docs/RequiredAndNullableApi.md#requiredAndNullablePostWithHttpInfo) | **POST** /requiredAndNullable | 
 *UploadApi* | [**uploadFilesPost**](docs/UploadApi.md#uploadFilesPost) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadFilesPostWithHttpInfo**](docs/UploadApi.md#uploadFilesPostWithHttpInfo) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadPost**](docs/UploadApi.md#uploadPost) | **POST** /upload | 
@@ -118,7 +121,9 @@ Class | Method | HTTP request | Description
 
 ## Documentation for Models
 
+ - [FileContent](docs/FileContent.md)
  - [Foo](docs/Foo.md)
+ - [RequiredAndNullable](docs/RequiredAndNullable.md)
 
 
 <a id="documentation-for-authorization"></a>
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/api/openapi.yaml b/samples/client/petstore/java/native-jackson3-jspecify/api/openapi.yaml
index b5f967c8460e..15c1f4176a50 100644
--- a/samples/client/petstore/java/native-jackson3-jspecify/api/openapi.yaml
+++ b/samples/client/petstore/java/native-jackson3-jspecify/api/openapi.yaml
@@ -6,6 +6,8 @@ info:
 servers:
 - url: /
 tags:
+- description: requiredAndNullable
+  name: requiredAndNullable
 - description: foo
   name: foo
 - description: upload
@@ -59,6 +61,27 @@ paths:
       - foo
       x-accepts:
       - application/json
+  /requiredAndNullable:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/RequiredAndNullable"
+        description: bodyWithRequiredAndNullableAttributes
+        required: true
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RequiredAndNullable"
+          description: response
+      tags:
+      - requiredAndNullable
+      x-content-type: application/json
+      x-accepts:
+      - application/json
   /upload:
     post:
       requestBody:
@@ -103,6 +126,10 @@ paths:
         style: simple
       responses:
         "200":
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FileContent"
           description: ok
       tags:
       - file
@@ -185,6 +212,62 @@ components:
       required:
       - requiredColor
       - requiredDt
+    RequiredAndNullable:
+      example:
+        str: str
+        file: ""
+        color: red
+        onlyRequired: onlyRequired
+        list:
+        - list
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          format: binary
+          nullable: true
+          type: string
+        color:
+          default: red
+          nullable: true
+          type: string
+        onlyRequired:
+          type: string
+        list:
+          items:
+            type: string
+          nullable: true
+          type: array
+      required:
+      - color
+      - file
+      - list
+      - onlyRequired
+      - str
+      type: object
+    FileContent:
+      example:
+        name: name
+        size: 0
+        virusScan: clean
+      properties:
+        name:
+          readOnly: true
+          type: string
+        size:
+          readOnly: true
+          type: integer
+        virusScan:
+          enum:
+          - clean
+          - detected
+          readOnly: true
+          type: string
+      required:
+      - name
+      type: object
     _upload_post_request:
       properties:
         file:
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/docs/FileApi.md b/samples/client/petstore/java/native-jackson3-jspecify/docs/FileApi.md
index 74ab70ddac94..b9f81d353ef9 100644
--- a/samples/client/petstore/java/native-jackson3-jspecify/docs/FileApi.md
+++ b/samples/client/petstore/java/native-jackson3-jspecify/docs/FileApi.md
@@ -11,7 +11,7 @@ All URIs are relative to *http://localhost*
 
 ## fileIdGet
 
-> void fileIdGet(id)
+> FileContent fileIdGet(id)
 
 
 
@@ -33,7 +33,8 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -54,8 +55,8 @@ public class Example {
 
 ### Return type
 
+[**FileContent**](FileContent.md)
 
-null (empty response body)
 
 ### Authorization
 
@@ -64,7 +65,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 ### HTTP response details
 | Status code | Description | Response headers |
@@ -73,7 +74,7 @@ No authorization required
 
 ## fileIdGetWithHttpInfo
 
-> ApiResponse<Void> fileIdGetWithHttpInfo(id)
+> ApiResponse<FileContent> fileIdGetWithHttpInfo(id)
 
 
 
@@ -96,9 +97,10 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            ApiResponse<Void> response = apiInstance.fileIdGetWithHttpInfo(id);
+            ApiResponse<FileContent> response = apiInstance.fileIdGetWithHttpInfo(id);
             System.out.println("Status code: " + response.getStatusCode());
             System.out.println("Response headers: " + response.getHeaders());
+            System.out.println("Response body: " + response.getData());
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -119,8 +121,8 @@ public class Example {
 
 ### Return type
 
+ApiResponse<[**FileContent**](FileContent.md)>
 
-ApiResponse<Void>
 
 ### Authorization
 
@@ -129,7 +131,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 ### HTTP response details
 | Status code | Description | Response headers |
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/docs/FileContent.md b/samples/client/petstore/java/native-jackson3-jspecify/docs/FileContent.md
new file mode 100644
index 000000000000..5b6654a0bf18
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/docs/FileContent.md
@@ -0,0 +1,24 @@
+
+
+# FileContent
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**name** | **String** |  |  [readonly] |
+|**size** | **Integer** |  |  [optional] [readonly] |
+|**virusScan** | [**VirusScanEnum**](#VirusScanEnum) |  |  [optional] [readonly] |
+
+
+
+## Enum: VirusScanEnum
+
+| Name | Value |
+|---- | -----|
+| CLEAN | &quot;clean&quot; |
+| DETECTED | &quot;detected&quot; |
+
+
+
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullable.md b/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullable.md
new file mode 100644
index 000000000000..ff4ade0f226d
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullable.md
@@ -0,0 +1,17 @@
+
+
+# RequiredAndNullable
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**str** | **String** |  |  |
+|**_file** | **File** |  |  |
+|**color** | **String** |  |  |
+|**onlyRequired** | **String** |  |  |
+|**_list** | **List&lt;String&gt;** |  |  |
+
+
+
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullableApi.md b/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullableApi.md
new file mode 100644
index 000000000000..eaad2b9ed25c
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/docs/RequiredAndNullableApi.md
@@ -0,0 +1,140 @@
+# RequiredAndNullableApi
+
+All URIs are relative to *http://localhost*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**requiredAndNullablePost**](RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable |  |
+| [**requiredAndNullablePostWithHttpInfo**](RequiredAndNullableApi.md#requiredAndNullablePostWithHttpInfo) | **POST** /requiredAndNullable |  |
+
+
+
+## requiredAndNullablePost
+
+> RequiredAndNullable requiredAndNullablePost(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            RequiredAndNullable result = apiInstance.requiredAndNullablePost(requiredAndNullable);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+[**RequiredAndNullable**](RequiredAndNullable.md)
+
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
+## requiredAndNullablePostWithHttpInfo
+
+> ApiResponse<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.ApiResponse;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            ApiResponse<RequiredAndNullable> response = apiInstance.requiredAndNullablePostWithHttpInfo(requiredAndNullable);
+            System.out.println("Status code: " + response.getStatusCode());
+            System.out.println("Response headers: " + response.getHeaders());
+            System.out.println("Response body: " + response.getData());
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            System.err.println("Reason: " + e.getResponseBody());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+ApiResponse<[**RequiredAndNullable**](RequiredAndNullable.md)>
+
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
index 668625401764..e1fd88a5dbfe 100644
--- a/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
@@ -18,6 +18,7 @@
 import org.openapitools.client.Configuration;
 import org.openapitools.client.Pair;
 
+import org.openapitools.client.model.FileContent;
 
 import tools.jackson.core.JacksonException;
 import tools.jackson.core.type.TypeReference;
@@ -166,10 +167,11 @@ private File prepareDownloadFile(HttpResponse<InputStream> response) throws IOEx
    * 
    * 
    * @param id  (required)
+   * @return FileContent
    * @throws ApiException if fails to make API call
    */
-  public void fileIdGet(String id) throws ApiException {
-    fileIdGet(id, null);
+  public FileContent fileIdGet(String id) throws ApiException {
+    return fileIdGet(id, null);
   }
 
   /**
@@ -177,20 +179,22 @@ public void fileIdGet(String id) throws ApiException {
    * 
    * @param id  (required)
    * @param headers Optional headers to include in the request
+   * @return FileContent
    * @throws ApiException if fails to make API call
    */
-  public void fileIdGet(String id, Map<String, String> headers) throws ApiException {
-    fileIdGetWithHttpInfo(id, headers);
+  public FileContent fileIdGet(String id, Map<String, String> headers) throws ApiException {
+    ApiResponse<FileContent> localVarResponse = fileIdGetWithHttpInfo(id, headers);
+    return localVarResponse.getData();
   }
 
   /**
    * 
    * 
    * @param id  (required)
-   * @return ApiResponse&lt;Void&gt;
+   * @return ApiResponse&lt;FileContent&gt;
    * @throws ApiException if fails to make API call
    */
-  public ApiResponse<Void> fileIdGetWithHttpInfo(String id) throws ApiException {
+  public ApiResponse<FileContent> fileIdGetWithHttpInfo(String id) throws ApiException {
     return fileIdGetWithHttpInfo(id, null);
   }
 
@@ -199,10 +203,10 @@ public ApiResponse<Void> fileIdGetWithHttpInfo(String id) throws ApiException {
    * 
    * @param id  (required)
    * @param headers Optional headers to include in the request
-   * @return ApiResponse&lt;Void&gt;
+   * @return ApiResponse&lt;FileContent&gt;
    * @throws ApiException if fails to make API call
    */
-  public ApiResponse<Void> fileIdGetWithHttpInfo(String id, Map<String, String> headers) throws ApiException {
+  public ApiResponse<FileContent> fileIdGetWithHttpInfo(String id, Map<String, String> headers) throws ApiException {
     HttpRequest.Builder localVarRequestBuilder = fileIdGetRequestBuilder(id, headers);
     try {
       HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
@@ -217,20 +221,31 @@ public ApiResponse<Void> fileIdGetWithHttpInfo(String id, Map<String, String> he
           throw getApiException("fileIdGet", localVarResponse);
         }
         localVarResponseBody = ApiClient.getResponseBody(localVarResponse);
-        if (localVarResponseBody != null) {
-          localVarResponseBody.readAllBytes();
+        if (localVarResponseBody == null) {
+          return new ApiResponse<FileContent>(
+              localVarResponse.statusCode(),
+              localVarResponse.headers().map(),
+              null
+          );
         }
-        return new ApiResponse<>(
+
+        
+        
+        String responseBody = new String(localVarResponseBody.readAllBytes());
+        FileContent responseValue = responseBody.isBlank()? null: memberVarObjectMapper.readValue(responseBody, new TypeReference<FileContent>() {});
+        
+
+        return new ApiResponse<FileContent>(
             localVarResponse.statusCode(),
             localVarResponse.headers().map(),
-            null
+            responseValue
         );
       } finally {
         if (localVarResponseBody != null) {
           localVarResponseBody.close();
         }
       }
-    } catch (IOException e) {
+    } catch (IOException | JacksonException e) {
       throw new ApiException(e);
     }
     catch (InterruptedException e) {
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..ded956fa8c44
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
@@ -0,0 +1,289 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.ApiResponse;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.Pair;
+
+import org.openapitools.client.model.RequiredAndNullable;
+
+import tools.jackson.core.JacksonException;
+import tools.jackson.core.type.TypeReference;
+import tools.jackson.databind.ObjectMapper;
+
+import java.io.InputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.http.HttpRequest;
+import java.nio.channels.Channels;
+import java.nio.channels.Pipe;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+import java.util.ArrayList;
+import java.util.StringJoiner;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
+
+@javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullableApi {
+  /**
+   * Utility class for extending HttpRequest.Builder functionality.
+   */
+  private static class HttpRequestBuilderExtensions {
+    /**
+     * Adds additional headers to the provided HttpRequest.Builder. Useful for adding method/endpoint specific headers.
+     *
+     * @param builder the HttpRequest.Builder to which headers will be added
+     * @param headers a map of header names and values to add; may be null
+     * @return the same HttpRequest.Builder instance with the additional headers set
+     */
+    static HttpRequest.Builder withAdditionalHeaders(HttpRequest.Builder builder, Map<String, String> headers) {
+        if (headers != null) {
+            for (Map.Entry<String, String> entry : headers.entrySet()) {
+                builder.header(entry.getKey(), entry.getValue());
+            }
+        }
+        return builder;
+    }
+  }
+  private final HttpClient memberVarHttpClient;
+  private final ObjectMapper memberVarObjectMapper;
+  private final String memberVarBaseUri;
+  private final Consumer<HttpRequest.Builder> memberVarInterceptor;
+  private final Duration memberVarReadTimeout;
+  private final Consumer<HttpResponse<InputStream>> memberVarResponseInterceptor;
+  private final Consumer<HttpResponse<InputStream>> memberVarAsyncResponseInterceptor;
+
+  public RequiredAndNullableApi() {
+    this(Configuration.getDefaultApiClient());
+  }
+
+  public RequiredAndNullableApi(ApiClient apiClient) {
+    memberVarHttpClient = apiClient.getHttpClient();
+    memberVarObjectMapper = apiClient.getObjectMapper();
+    memberVarBaseUri = apiClient.getBaseUri();
+    memberVarInterceptor = apiClient.getRequestInterceptor();
+    memberVarReadTimeout = apiClient.getReadTimeout();
+    memberVarResponseInterceptor = apiClient.getResponseInterceptor();
+    memberVarAsyncResponseInterceptor = apiClient.getAsyncResponseInterceptor();
+  }
+
+
+  protected ApiException getApiException(String operationId, HttpResponse<InputStream> response) throws IOException {
+    InputStream responseBody = ApiClient.getResponseBody(response);
+    String body = null;
+    try {
+      body = responseBody == null ? null : new String(responseBody.readAllBytes());
+    } finally {
+      if (responseBody != null) {
+        responseBody.close();
+      }
+    }
+    String message = formatExceptionMessage(operationId, response.statusCode(), body);
+    return new ApiException(response.statusCode(), message, response.headers(), body);
+  }
+
+  private String formatExceptionMessage(String operationId, int statusCode, String body) {
+    if (body == null || body.isEmpty()) {
+      body = "[no body]";
+    }
+    return operationId + " call failed with: " + statusCode + " - " + body;
+  }
+
+  /**
+   * Download file from the given response.
+   *
+   * @param response Response
+   * @return File
+   * @throws ApiException If fail to read file content from response and write to disk
+   */
+  public File downloadFileFromResponse(HttpResponse<InputStream> response, InputStream responseBody) throws ApiException {
+    if (responseBody == null) {
+      throw new ApiException(new IOException("Response body is empty"));
+    }
+    try {
+      File file = prepareDownloadFile(response);
+      java.nio.file.Files.copy(responseBody, file.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING);
+      return file;
+    } catch (IOException e) {
+      throw new ApiException(e);
+    }
+  }
+
+  /**
+   * <p>Prepare the file for download from the response.</p>
+   *
+   * @param response a {@link java.net.http.HttpResponse} object.
+   * @return a {@link java.io.File} object.
+   * @throws java.io.IOException if any.
+   */
+  private File prepareDownloadFile(HttpResponse<InputStream> response) throws IOException {
+    String filename = null;
+    java.util.Optional<String> contentDisposition = response.headers().firstValue("Content-Disposition");
+    if (contentDisposition.isPresent() && !"".equals(contentDisposition.get())) {
+      // Get filename from the Content-Disposition header.
+      java.util.regex.Pattern pattern = java.util.regex.Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?");
+      java.util.regex.Matcher matcher = pattern.matcher(contentDisposition.get());
+      if (matcher.find())
+        filename = matcher.group(1);
+    }
+    File file = null;
+    if (filename != null) {
+      java.nio.file.Path tempDir = java.nio.file.Files.createTempDirectory("swagger-gen-native");
+      java.nio.file.Path filePath = java.nio.file.Files.createFile(tempDir.resolve(filename));
+      file = filePath.toFile();
+      tempDir.toFile().deleteOnExit();   // best effort cleanup
+      file.deleteOnExit(); // best effort cleanup
+    } else {
+      file = java.nio.file.Files.createTempFile("download-", "").toFile();
+      file.deleteOnExit(); // best effort cleanup
+    }
+    return file;
+  }
+
+  /**
+   * 
+   * 
+   * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+   * @return RequiredAndNullable
+   * @throws ApiException if fails to make API call
+   */
+  public RequiredAndNullable requiredAndNullablePost(RequiredAndNullable requiredAndNullable) throws ApiException {
+    return requiredAndNullablePost(requiredAndNullable, null);
+  }
+
+  /**
+   * 
+   * 
+   * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+   * @param headers Optional headers to include in the request
+   * @return RequiredAndNullable
+   * @throws ApiException if fails to make API call
+   */
+  public RequiredAndNullable requiredAndNullablePost(RequiredAndNullable requiredAndNullable, Map<String, String> headers) throws ApiException {
+    ApiResponse<RequiredAndNullable> localVarResponse = requiredAndNullablePostWithHttpInfo(requiredAndNullable, headers);
+    return localVarResponse.getData();
+  }
+
+  /**
+   * 
+   * 
+   * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+   * @return ApiResponse&lt;RequiredAndNullable&gt;
+   * @throws ApiException if fails to make API call
+   */
+  public ApiResponse<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable) throws ApiException {
+    return requiredAndNullablePostWithHttpInfo(requiredAndNullable, null);
+  }
+
+  /**
+   * 
+   * 
+   * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+   * @param headers Optional headers to include in the request
+   * @return ApiResponse&lt;RequiredAndNullable&gt;
+   * @throws ApiException if fails to make API call
+   */
+  public ApiResponse<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable, Map<String, String> headers) throws ApiException {
+    HttpRequest.Builder localVarRequestBuilder = requiredAndNullablePostRequestBuilder(requiredAndNullable, headers);
+    try {
+      HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
+          localVarRequestBuilder.build(),
+          HttpResponse.BodyHandlers.ofInputStream());
+      if (memberVarResponseInterceptor != null) {
+        memberVarResponseInterceptor.accept(localVarResponse);
+      }
+      InputStream localVarResponseBody = null;
+      try {
+        if (localVarResponse.statusCode()/ 100 != 2) {
+          throw getApiException("requiredAndNullablePost", localVarResponse);
+        }
+        localVarResponseBody = ApiClient.getResponseBody(localVarResponse);
+        if (localVarResponseBody == null) {
+          return new ApiResponse<RequiredAndNullable>(
+              localVarResponse.statusCode(),
+              localVarResponse.headers().map(),
+              null
+          );
+        }
+
+        
+        
+        String responseBody = new String(localVarResponseBody.readAllBytes());
+        RequiredAndNullable responseValue = responseBody.isBlank()? null: memberVarObjectMapper.readValue(responseBody, new TypeReference<RequiredAndNullable>() {});
+        
+
+        return new ApiResponse<RequiredAndNullable>(
+            localVarResponse.statusCode(),
+            localVarResponse.headers().map(),
+            responseValue
+        );
+      } finally {
+        if (localVarResponseBody != null) {
+          localVarResponseBody.close();
+        }
+      }
+    } catch (IOException | JacksonException e) {
+      throw new ApiException(e);
+    }
+    catch (InterruptedException e) {
+      Thread.currentThread().interrupt();
+      throw new ApiException(e);
+    }
+  }
+
+  private HttpRequest.Builder requiredAndNullablePostRequestBuilder(RequiredAndNullable requiredAndNullable, Map<String, String> headers) throws ApiException {
+    // verify the required parameter 'requiredAndNullable' is set
+    if (requiredAndNullable == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredAndNullable' when calling requiredAndNullablePost");
+    }
+
+    HttpRequest.Builder localVarRequestBuilder = HttpRequest.newBuilder();
+
+    String localVarPath = "/requiredAndNullable";
+
+    localVarRequestBuilder.uri(URI.create(memberVarBaseUri + localVarPath));
+
+    localVarRequestBuilder.header("Content-Type", "application/json");
+    localVarRequestBuilder.header("Accept", "application/json");
+
+    try {
+      byte[] localVarPostBody = memberVarObjectMapper.writeValueAsBytes(requiredAndNullable);
+      localVarRequestBuilder.method("POST", HttpRequest.BodyPublishers.ofByteArray(localVarPostBody));
+    } catch (JacksonException e) {
+      throw new ApiException(e);
+    }
+    if (memberVarReadTimeout != null) {
+      localVarRequestBuilder.timeout(memberVarReadTimeout);
+    }
+    // Add custom headers if provided
+    localVarRequestBuilder = HttpRequestBuilderExtensions.withAdditionalHeaders(localVarRequestBuilder, headers);
+    if (memberVarInterceptor != null) {
+      memberVarInterceptor.accept(localVarRequestBuilder);
+    }
+    return localVarRequestBuilder;
+  }
+
+}
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
new file mode 100644
index 000000000000..adbcdd81a78a
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
@@ -0,0 +1,294 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import java.util.StringJoiner;
+import java.util.Objects;
+import java.util.Map;
+import java.util.HashMap;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.util.Arrays;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+
+import org.openapitools.client.ApiClient;
+/**
+ * FileContent
+ */
+@JsonPropertyOrder({
+  FileContent.JSON_PROPERTY_NAME,
+  FileContent.JSON_PROPERTY_SIZE,
+  FileContent.JSON_PROPERTY_VIRUS_SCAN
+})
+@javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+  public static final String JSON_PROPERTY_NAME = "name";
+  
+  private String name;
+
+  public static final String JSON_PROPERTY_SIZE = "size";
+  
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN(String.valueOf("clean")),
+    
+    DETECTED(String.valueOf("detected"));
+
+    private String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_VIRUS_SCAN = "virusScan";
+  
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() { 
+  }
+
+  @JsonCreator
+  public FileContent(
+    @JsonProperty(JSON_PROPERTY_NAME) String name, 
+    @JsonProperty(JSON_PROPERTY_SIZE) Integer size, 
+    @JsonProperty(JSON_PROPERTY_VIRUS_SCAN) VirusScanEnum virusScan
+  ) {
+  this();
+    this.name = name;
+    this.size = size;
+    this.virusScan = virusScan;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_NAME, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public String getName() {
+    return name;
+  }
+
+
+
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_SIZE, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+
+
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_VIRUS_SCAN, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+
+
+
+  /**
+   * Return true if this FileContent object is equal to o.
+   */
+  @Override
+  public boolean equals(Object o) {
+    return EqualsBuilder.reflectionEquals(this, o, false, null, true);
+  }
+
+  @Override
+  public int hashCode() {
+    return HashCodeBuilder.reflectionHashCode(this);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  /**
+   * Convert the instance into URL query string.
+   *
+   * @return URL query string
+   */
+  public String toUrlQueryString() {
+    return toUrlQueryString(null);
+  }
+
+  /**
+   * Convert the instance into URL query string.
+   *
+   * @param prefix prefix of the query string
+   * @return URL query string
+   */
+  public String toUrlQueryString(String prefix) {
+    String suffix = "";
+    String containerSuffix = "";
+    String containerPrefix = "";
+    if (prefix == null) {
+      // style=form, explode=true, e.g. /pet?name=cat&type=manx
+      prefix = "";
+    } else {
+      // deepObject style e.g. /pet?id[name]=cat&id[type]=manx
+      prefix = prefix + "[";
+      suffix = "]";
+      containerSuffix = "]";
+      containerPrefix = "[";
+    }
+
+    StringJoiner joiner = new StringJoiner("&");
+
+    // add `name` to the URL query string
+    if (getName() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%sname%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getName()))));
+    }
+
+    // add `size` to the URL query string
+    if (getSize() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%ssize%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getSize()))));
+    }
+
+    // add `virusScan` to the URL query string
+    if (getVirusScan() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%svirusScan%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getVirusScan()))));
+    }
+
+    return joiner.toString();
+  }
+
+    public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size = size;
+      return this;
+    }
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan = virusScan;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    return new FileContent.Builder()
+      .name(getName())
+      .size(getSize())
+      .virusScan(getVirusScan());
+  }
+
+}
+
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..53202eaf7653
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
@@ -0,0 +1,372 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import java.util.StringJoiner;
+import java.util.Objects;
+import java.util.Map;
+import java.util.HashMap;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+
+import org.openapitools.client.ApiClient;
+/**
+ * RequiredAndNullable
+ */
+@JsonPropertyOrder({
+  RequiredAndNullable.JSON_PROPERTY_STR,
+  RequiredAndNullable.JSON_PROPERTY_FILE,
+  RequiredAndNullable.JSON_PROPERTY_COLOR,
+  RequiredAndNullable.JSON_PROPERTY_ONLY_REQUIRED,
+  RequiredAndNullable.JSON_PROPERTY_LIST
+})
+@javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+  public static final String JSON_PROPERTY_STR = "str";
+  
+  private @Nullable String str;
+
+  public static final String JSON_PROPERTY_FILE = "file";
+  
+  private @Nullable File _file;
+
+  public static final String JSON_PROPERTY_COLOR = "color";
+  
+  private @Nullable String color = "red";
+
+  public static final String JSON_PROPERTY_ONLY_REQUIRED = "onlyRequired";
+  
+  private String onlyRequired;
+
+  public static final String JSON_PROPERTY_LIST = "list";
+  
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() { 
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public @Nullable String getStr() {
+    return str;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+
+  public RequiredAndNullable _file(@Nullable File _file) {
+    this._file = _file;
+    return this;
+  }
+
+  /**
+   * Get _file
+   * @return _file
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public @Nullable File getFile() {
+    return _file;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setFile(@Nullable File _file) {
+    this._file = _file;
+  }
+
+
+  public RequiredAndNullable color(@Nullable String color) {
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public @Nullable String getColor() {
+    return color;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+
+  /**
+   * Return true if this RequiredAndNullable object is equal to o.
+   */
+  @Override
+  public boolean equals(Object o) {
+    return EqualsBuilder.reflectionEquals(this, o, false, null, true);
+  }
+
+  @Override
+  public int hashCode() {
+    return HashCodeBuilder.reflectionHashCode(this);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    _file: ").append(toIndentedString(_file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  /**
+   * Convert the instance into URL query string.
+   *
+   * @return URL query string
+   */
+  public String toUrlQueryString() {
+    return toUrlQueryString(null);
+  }
+
+  /**
+   * Convert the instance into URL query string.
+   *
+   * @param prefix prefix of the query string
+   * @return URL query string
+   */
+  public String toUrlQueryString(String prefix) {
+    String suffix = "";
+    String containerSuffix = "";
+    String containerPrefix = "";
+    if (prefix == null) {
+      // style=form, explode=true, e.g. /pet?name=cat&type=manx
+      prefix = "";
+    } else {
+      // deepObject style e.g. /pet?id[name]=cat&id[type]=manx
+      prefix = prefix + "[";
+      suffix = "]";
+      containerSuffix = "]";
+      containerPrefix = "[";
+    }
+
+    StringJoiner joiner = new StringJoiner("&");
+
+    // add `str` to the URL query string
+    if (getStr() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%sstr%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getStr()))));
+    }
+
+    // add `file` to the URL query string
+    if (getFile() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%sfile%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getFile()))));
+    }
+
+    // add `color` to the URL query string
+    if (getColor() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%scolor%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getColor()))));
+    }
+
+    // add `onlyRequired` to the URL query string
+    if (getOnlyRequired() != null) {
+      joiner.add(String.format(java.util.Locale.ROOT, "%sonlyRequired%s=%s", prefix, suffix, ApiClient.urlEncode(ApiClient.valueToString(getOnlyRequired()))));
+    }
+
+    // add `list` to the URL query string
+    if (getList() != null) {
+      for (int i = 0; i < getList().size(); i++) {
+        joiner.add(String.format(java.util.Locale.ROOT, "%slist%s%s=%s", prefix, suffix,
+            "".equals(suffix) ? "" : String.format(java.util.Locale.ROOT, "%s%d%s", containerPrefix, i, containerSuffix),
+            ApiClient.urlEncode(ApiClient.valueToString(getList().get(i)))));
+      }
+    }
+
+    return joiner.toString();
+  }
+
+    public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str = str;
+      return this;
+    }
+    public RequiredAndNullable.Builder _file(@Nullable File _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color = color;
+      return this;
+    }
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired = onlyRequired;
+      return this;
+    }
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+
+
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable.
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    return new RequiredAndNullable.Builder()
+      .str(getStr())
+      ._file(getFile())
+      .color(getColor())
+      .onlyRequired(getOnlyRequired())
+      ._list(getList());
+  }
+
+}
+
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
new file mode 100644
index 000000000000..e978305a1590
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
@@ -0,0 +1,54 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiException;
+import org.openapitools.client.model.RequiredAndNullable;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+
+/**
+ * API tests for RequiredAndNullableApi
+ */
+@Disabled
+public class RequiredAndNullableApiTest {
+
+    private final RequiredAndNullableApi api = new RequiredAndNullableApi();
+
+    
+    /**
+     * 
+     *
+     * 
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void requiredAndNullablePostTest() throws ApiException {
+        RequiredAndNullable requiredAndNullable = null;
+        RequiredAndNullable response = 
+        api.requiredAndNullablePost(requiredAndNullable);
+        
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
new file mode 100644
index 000000000000..eafa2e0aaa1d
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
@@ -0,0 +1,56 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.util.Arrays;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for FileContent
+ */
+class FileContentTest {
+    private final FileContent model = new FileContent();
+
+    /**
+     * Model tests for FileContent
+     */
+    @Test
+    void testFileContent() {
+        // TODO: test FileContent
+    }
+
+    /**
+     * Test the property 'name'
+     */
+    @Test
+    void nameTest() {
+        // TODO: test name
+    }
+
+    /**
+     * Test the property 'size'
+     */
+    @Test
+    void sizeTest() {
+        // TODO: test size
+    }
+
+}
diff --git a/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
new file mode 100644
index 000000000000..15c3a3b980b5
--- /dev/null
+++ b/samples/client/petstore/java/native-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
@@ -0,0 +1,73 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.Arrays;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for RequiredAndNullable
+ */
+class RequiredAndNullableTest {
+    private final RequiredAndNullable model = new RequiredAndNullable();
+
+    /**
+     * Model tests for RequiredAndNullable
+     */
+    @Test
+    void testRequiredAndNullable() {
+        // TODO: test RequiredAndNullable
+    }
+
+    /**
+     * Test the property 'str'
+     */
+    @Test
+    void strTest() {
+        // TODO: test str
+    }
+
+    /**
+     * Test the property '_file'
+     */
+    @Test
+    void _fileTest() {
+        // TODO: test _file
+    }
+
+    /**
+     * Test the property 'color'
+     */
+    @Test
+    void colorTest() {
+        // TODO: test color
+    }
+
+    /**
+     * Test the property 'onlyRequired'
+     */
+    @Test
+    void onlyRequiredTest() {
+        // TODO: test onlyRequired
+    }
+
+}
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
index e7440e03ef92..6569aaded6ce 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -304,7 +304,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -348,7 +348,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -424,7 +424,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -468,7 +468,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/.openapi-generator/FILES b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/.openapi-generator/FILES
index 905482ebbf2c..a9762735bc0b 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/.openapi-generator/FILES
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/.openapi-generator/FILES
@@ -6,8 +6,11 @@ api/openapi.yaml
 build.gradle
 build.sbt
 docs/FileApi.md
+docs/FileContent.md
 docs/Foo.md
 docs/FooApi.md
+docs/RequiredAndNullable.md
+docs/RequiredAndNullableApi.md
 docs/UploadApi.md
 git_push.sh
 gradle.properties
@@ -27,12 +30,15 @@ src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/StringUtil.java
 src/main/java/org/openapitools/client/api/FileApi.java
 src/main/java/org/openapitools/client/api/FooApi.java
+src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/client/api/UploadApi.java
 src/main/java/org/openapitools/client/api/package-info.java
 src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
 src/main/java/org/openapitools/client/auth/Authentication.java
 src/main/java/org/openapitools/client/auth/HttpBasicAuth.java
 src/main/java/org/openapitools/client/auth/HttpBearerAuth.java
+src/main/java/org/openapitools/client/model/FileContent.java
 src/main/java/org/openapitools/client/model/Foo.java
+src/main/java/org/openapitools/client/model/RequiredAndNullable.java
 src/main/java/org/openapitools/client/model/package-info.java
 src/main/java/org/openapitools/client/package-info.java
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/README.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/README.md
index 4d406688dd86..c8dcc331bcce 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/README.md
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/README.md
@@ -95,7 +95,8 @@ public class FileApiExample {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (HttpStatusCodeException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getStatusCode().value());
@@ -116,13 +117,16 @@ Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
 *FileApi* | [**fileIdGet**](docs/FileApi.md#fileIdGet) | **GET** /file/{id} | 
 *FooApi* | [**fooDtParamGet**](docs/FooApi.md#fooDtParamGet) | **GET** /foo/{dtParam} | 
+*RequiredAndNullableApi* | [**requiredAndNullablePost**](docs/RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable | 
 *UploadApi* | [**uploadFilesPost**](docs/UploadApi.md#uploadFilesPost) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadPost**](docs/UploadApi.md#uploadPost) | **POST** /upload | 
 
 
 ## Documentation for Models
 
+ - [FileContent](docs/FileContent.md)
  - [Foo](docs/Foo.md)
+ - [RequiredAndNullable](docs/RequiredAndNullable.md)
 
 
 <a id="documentation-for-authorization"></a>
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/api/openapi.yaml b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/api/openapi.yaml
index b5f967c8460e..15c1f4176a50 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/api/openapi.yaml
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/api/openapi.yaml
@@ -6,6 +6,8 @@ info:
 servers:
 - url: /
 tags:
+- description: requiredAndNullable
+  name: requiredAndNullable
 - description: foo
   name: foo
 - description: upload
@@ -59,6 +61,27 @@ paths:
       - foo
       x-accepts:
       - application/json
+  /requiredAndNullable:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/RequiredAndNullable"
+        description: bodyWithRequiredAndNullableAttributes
+        required: true
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RequiredAndNullable"
+          description: response
+      tags:
+      - requiredAndNullable
+      x-content-type: application/json
+      x-accepts:
+      - application/json
   /upload:
     post:
       requestBody:
@@ -103,6 +126,10 @@ paths:
         style: simple
       responses:
         "200":
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FileContent"
           description: ok
       tags:
       - file
@@ -185,6 +212,62 @@ components:
       required:
       - requiredColor
       - requiredDt
+    RequiredAndNullable:
+      example:
+        str: str
+        file: ""
+        color: red
+        onlyRequired: onlyRequired
+        list:
+        - list
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          format: binary
+          nullable: true
+          type: string
+        color:
+          default: red
+          nullable: true
+          type: string
+        onlyRequired:
+          type: string
+        list:
+          items:
+            type: string
+          nullable: true
+          type: array
+      required:
+      - color
+      - file
+      - list
+      - onlyRequired
+      - str
+      type: object
+    FileContent:
+      example:
+        name: name
+        size: 0
+        virusScan: clean
+      properties:
+        name:
+          readOnly: true
+          type: string
+        size:
+          readOnly: true
+          type: integer
+        virusScan:
+          enum:
+          - clean
+          - detected
+          readOnly: true
+          type: string
+      required:
+      - name
+      type: object
     _upload_post_request:
       properties:
         file:
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileApi.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileApi.md
index 4e6607ae5a71..59683371bc55 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileApi.md
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileApi.md
@@ -10,7 +10,7 @@ All URIs are relative to *http://localhost*
 
 ## fileIdGet
 
-> fileIdGet(id)
+> FileContent fileIdGet(id)
 
 
 
@@ -32,7 +32,8 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -53,7 +54,7 @@ public class Example {
 
 ### Return type
 
-null (empty response body)
+[**FileContent**](FileContent.md)
 
 ### Authorization
 
@@ -62,7 +63,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 
 ### HTTP response details
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileContent.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileContent.md
new file mode 100644
index 000000000000..5b6654a0bf18
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/FileContent.md
@@ -0,0 +1,24 @@
+
+
+# FileContent
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**name** | **String** |  |  [readonly] |
+|**size** | **Integer** |  |  [optional] [readonly] |
+|**virusScan** | [**VirusScanEnum**](#VirusScanEnum) |  |  [optional] [readonly] |
+
+
+
+## Enum: VirusScanEnum
+
+| Name | Value |
+|---- | -----|
+| CLEAN | &quot;clean&quot; |
+| DETECTED | &quot;detected&quot; |
+
+
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullable.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullable.md
new file mode 100644
index 000000000000..ff4ade0f226d
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullable.md
@@ -0,0 +1,17 @@
+
+
+# RequiredAndNullable
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**str** | **String** |  |  |
+|**_file** | **File** |  |  |
+|**color** | **String** |  |  |
+|**onlyRequired** | **String** |  |  |
+|**_list** | **List&lt;String&gt;** |  |  |
+
+
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullableApi.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullableApi.md
new file mode 100644
index 000000000000..ada434bf0b9e
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/docs/RequiredAndNullableApi.md
@@ -0,0 +1,73 @@
+# RequiredAndNullableApi
+
+All URIs are relative to *http://localhost*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**requiredAndNullablePost**](RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable |  |
+
+
+
+## requiredAndNullablePost
+
+> RequiredAndNullable requiredAndNullablePost(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            RequiredAndNullable result = apiInstance.requiredAndNullablePost(requiredAndNullable);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+[**RequiredAndNullable**](RequiredAndNullable.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/FileApi.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/FileApi.java
index 4f1bf741d207..a391a80e7577 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/FileApi.java
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/FileApi.java
@@ -2,6 +2,7 @@
 
 import org.openapitools.client.ApiClient;
 
+import org.openapitools.client.model.FileContent;
 
 import java.util.HashMap;
 import java.util.List;
@@ -48,6 +49,7 @@ public void setApiClient(ApiClient apiClient) {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
     private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientResponseException {
@@ -66,14 +68,16 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientRespon
         final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<>();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<>();
 
-        final String[] localVarAccepts = { };
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
         final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
         final String[] localVarContentTypes = { };
         final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
 
         String[] localVarAuthNames = new String[] {  };
 
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
         return apiClient.invokeAPI("/file/{id}", HttpMethod.GET, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
     }
 
@@ -82,11 +86,12 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientRespon
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
-    public void fileIdGet(String id) throws RestClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
-        fileIdGetRequestCreation(id).body(localVarReturnType);
+    public FileContent fileIdGet(String id) throws RestClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return fileIdGetRequestCreation(id).body(localVarReturnType);
     }
 
     /**
@@ -94,10 +99,11 @@ public void fileIdGet(String id) throws RestClientResponseException {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return ResponseEntity&lt;FileContent&gt;
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
-    public ResponseEntity<Void> fileIdGetWithHttpInfo(String id) throws RestClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
+    public ResponseEntity<FileContent> fileIdGetWithHttpInfo(String id) throws RestClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
         return fileIdGetRequestCreation(id).toEntity(localVarReturnType);
     }
 
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..cc0e7c9ca9fa
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
@@ -0,0 +1,121 @@
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+
+import org.openapitools.client.model.RequiredAndNullable;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestClient.ResponseSpec;
+import org.springframework.web.client.RestClientResponseException;
+
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullableApi {
+    private ApiClient apiClient;
+
+    public RequiredAndNullableApi() {
+        this(new ApiClient());
+    }
+
+    public RequiredAndNullableApi(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    public ApiClient getApiClient() {
+        return apiClient;
+    }
+
+    public void setApiClient(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    private ResponseSpec requiredAndNullablePostRequestCreation(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        Object postBody = requiredAndNullable;
+        // verify the required parameter 'requiredAndNullable' is set
+        if (requiredAndNullable == null) {
+            throw new RestClientResponseException("Missing the required parameter 'requiredAndNullable' when calling requiredAndNullablePost", HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.getReasonPhrase(), null, null, null);
+        }
+        // create path and map variables
+        final Map<String, Object> pathParams = new HashMap<>();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<>();
+        final HttpHeaders headerParams = new HttpHeaders();
+        final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<>();
+        final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { 
+            "application/json"
+        };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        String[] localVarAuthNames = new String[] {  };
+
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return apiClient.invokeAPI("/requiredAndNullable", HttpMethod.POST, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public RequiredAndNullable requiredAndNullablePost(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).body(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseEntity&lt;RequiredAndNullable&gt;
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).toEntity(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseSpec
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public ResponseSpec requiredAndNullablePostWithResponseSpec(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        return requiredAndNullablePostRequestCreation(requiredAndNullable);
+    }
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/FileContent.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/FileContent.java
new file mode 100644
index 000000000000..b0f00682525b
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/FileContent.java
@@ -0,0 +1,247 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * FileContent
+ */
+@JsonPropertyOrder({
+  FileContent.JSON_PROPERTY_NAME,
+  FileContent.JSON_PROPERTY_SIZE,
+  FileContent.JSON_PROPERTY_VIRUS_SCAN
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+  public static final String JSON_PROPERTY_NAME = "name";
+  
+  private String name;
+
+  public static final String JSON_PROPERTY_SIZE = "size";
+  
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN(String.valueOf("clean")),
+    
+    DETECTED(String.valueOf("detected"));
+
+    private String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_VIRUS_SCAN = "virusScan";
+  
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+  }
+  /**
+   * Constructor with only readonly parameters and all parameters
+   */
+  @JsonCreator
+  public FileContent(
+    @JsonProperty(JSON_PROPERTY_NAME) String name, 
+    @JsonProperty(JSON_PROPERTY_SIZE) Integer size, 
+    @JsonProperty(JSON_PROPERTY_VIRUS_SCAN) VirusScanEnum virusScan
+  ) {
+    this();
+    this.name = name;
+    this.size = size;
+    this.virusScan = virusScan;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_NAME, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getName() {
+    return name;
+  }
+
+
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_SIZE, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_VIRUS_SCAN, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size = size;
+      return this;
+    }
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan = virusScan;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    return new FileContent.Builder()
+      .name(getName())
+      .size(getSize())
+      .virusScan(getVirusScan());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/Foo.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/Foo.java
index 3397bcbf9b49..e5cc9c951158 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/Foo.java
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/Foo.java
@@ -317,7 +317,7 @@ public Foo nullableListMinIntems(@Nullable List<java.time.Instant> nullableListM
   }
 
   public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsItem) {
-    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent()) {
+    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent() || this.nullableListMinIntems.get() == null) {
       this.nullableListMinIntems = JsonNullable.<List<java.time.Instant>>of(new ArrayList<>());
     }
     try {
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/RequiredAndNullable.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..55653e9e6161
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
@@ -0,0 +1,328 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * RequiredAndNullable
+ */
+@JsonPropertyOrder({
+  RequiredAndNullable.JSON_PROPERTY_STR,
+  RequiredAndNullable.JSON_PROPERTY_FILE,
+  RequiredAndNullable.JSON_PROPERTY_COLOR,
+  RequiredAndNullable.JSON_PROPERTY_ONLY_REQUIRED,
+  RequiredAndNullable.JSON_PROPERTY_LIST
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+  public static final String JSON_PROPERTY_STR = "str";
+  
+  private @Nullable String str;
+
+  public static final String JSON_PROPERTY_FILE = "file";
+  
+  private @Nullable File _file;
+
+  public static final String JSON_PROPERTY_COLOR = "color";
+  
+  private @Nullable String color = "red";
+
+  public static final String JSON_PROPERTY_ONLY_REQUIRED = "onlyRequired";
+  
+  private String onlyRequired;
+
+  public static final String JSON_PROPERTY_LIST = "list";
+  
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() {
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public RequiredAndNullable(@JsonProperty(JSON_PROPERTY_STR) @Nullable String str, @JsonProperty(JSON_PROPERTY_FILE) @Nullable File _file, @JsonProperty(JSON_PROPERTY_COLOR) @Nullable String color, @JsonProperty(JSON_PROPERTY_ONLY_REQUIRED) String onlyRequired, @JsonProperty(JSON_PROPERTY_LIST) @Nullable List<String> _list) {
+    this.str = str;
+    this._file = _file;
+    this.color = color;
+    this.onlyRequired = onlyRequired;
+    this._list = _list;
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getStr() {
+    return str;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable _file(@Nullable File _file) {
+    
+    this._file = _file;
+    return this;
+  }
+
+  /**
+   * Get _file
+   * @return _file
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable File getFile() {
+    return _file;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setFile(@Nullable File _file) {
+    this._file = _file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getColor() {
+    return color;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this._file, requiredAndNullable._file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, _file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    _file: ").append(toIndentedString(_file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str = str;
+      return this;
+    }
+    public RequiredAndNullable.Builder _file(@Nullable File _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color = color;
+      return this;
+    }
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired = onlyRequired;
+      return this;
+    }
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+
+
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable.
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    return new RequiredAndNullable.Builder()
+      .str(getStr())
+      ._file(getFile())
+      .color(getColor())
+      .onlyRequired(getOnlyRequired())
+      ._list(getList());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
new file mode 100644
index 000000000000..41e971ae1aa5
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
@@ -0,0 +1,48 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.model.RequiredAndNullable;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * API tests for RequiredAndNullableApi
+ */
+@Disabled
+public class RequiredAndNullableApiTest {
+
+    private final RequiredAndNullableApi api = new RequiredAndNullableApi();
+
+    
+    /**
+     * 
+     *
+     * 
+     */
+    @Test
+    public void requiredAndNullablePostTest()  {
+        RequiredAndNullable requiredAndNullable = null;
+        RequiredAndNullable response = api.requiredAndNullablePost(requiredAndNullable);
+
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/FileContentTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/FileContentTest.java
new file mode 100644
index 000000000000..bc686732b1ca
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/FileContentTest.java
@@ -0,0 +1,55 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for FileContent
+ */
+class FileContentTest {
+    private final FileContent model = new FileContent();
+
+    /**
+     * Model tests for FileContent
+     */
+    @Test
+    void testFileContent() {
+        // TODO: test FileContent
+    }
+
+    /**
+     * Test the property 'name'
+     */
+    @Test
+    void nameTest() {
+        // TODO: test name
+    }
+
+    /**
+     * Test the property 'size'
+     */
+    @Test
+    void sizeTest() {
+        // TODO: test size
+    }
+
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
new file mode 100644
index 000000000000..3d3388460faf
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify-openapiNullable/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
@@ -0,0 +1,72 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for RequiredAndNullable
+ */
+class RequiredAndNullableTest {
+    private final RequiredAndNullable model = new RequiredAndNullable();
+
+    /**
+     * Model tests for RequiredAndNullable
+     */
+    @Test
+    void testRequiredAndNullable() {
+        // TODO: test RequiredAndNullable
+    }
+
+    /**
+     * Test the property 'str'
+     */
+    @Test
+    void strTest() {
+        // TODO: test str
+    }
+
+    /**
+     * Test the property '_file'
+     */
+    @Test
+    void _fileTest() {
+        // TODO: test _file
+    }
+
+    /**
+     * Test the property 'color'
+     */
+    @Test
+    void colorTest() {
+        // TODO: test color
+    }
+
+    /**
+     * Test the property 'onlyRequired'
+     */
+    @Test
+    void onlyRequiredTest() {
+        // TODO: test onlyRequired
+    }
+
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
index 905482ebbf2c..a9762735bc0b 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
@@ -6,8 +6,11 @@ api/openapi.yaml
 build.gradle
 build.sbt
 docs/FileApi.md
+docs/FileContent.md
 docs/Foo.md
 docs/FooApi.md
+docs/RequiredAndNullable.md
+docs/RequiredAndNullableApi.md
 docs/UploadApi.md
 git_push.sh
 gradle.properties
@@ -27,12 +30,15 @@ src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/StringUtil.java
 src/main/java/org/openapitools/client/api/FileApi.java
 src/main/java/org/openapitools/client/api/FooApi.java
+src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/client/api/UploadApi.java
 src/main/java/org/openapitools/client/api/package-info.java
 src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
 src/main/java/org/openapitools/client/auth/Authentication.java
 src/main/java/org/openapitools/client/auth/HttpBasicAuth.java
 src/main/java/org/openapitools/client/auth/HttpBearerAuth.java
+src/main/java/org/openapitools/client/model/FileContent.java
 src/main/java/org/openapitools/client/model/Foo.java
+src/main/java/org/openapitools/client/model/RequiredAndNullable.java
 src/main/java/org/openapitools/client/model/package-info.java
 src/main/java/org/openapitools/client/package-info.java
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/README.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/README.md
index 4d406688dd86..c8dcc331bcce 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/README.md
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/README.md
@@ -95,7 +95,8 @@ public class FileApiExample {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (HttpStatusCodeException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getStatusCode().value());
@@ -116,13 +117,16 @@ Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
 *FileApi* | [**fileIdGet**](docs/FileApi.md#fileIdGet) | **GET** /file/{id} | 
 *FooApi* | [**fooDtParamGet**](docs/FooApi.md#fooDtParamGet) | **GET** /foo/{dtParam} | 
+*RequiredAndNullableApi* | [**requiredAndNullablePost**](docs/RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable | 
 *UploadApi* | [**uploadFilesPost**](docs/UploadApi.md#uploadFilesPost) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadPost**](docs/UploadApi.md#uploadPost) | **POST** /upload | 
 
 
 ## Documentation for Models
 
+ - [FileContent](docs/FileContent.md)
  - [Foo](docs/Foo.md)
+ - [RequiredAndNullable](docs/RequiredAndNullable.md)
 
 
 <a id="documentation-for-authorization"></a>
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/api/openapi.yaml b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/api/openapi.yaml
index b5f967c8460e..15c1f4176a50 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/api/openapi.yaml
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/api/openapi.yaml
@@ -6,6 +6,8 @@ info:
 servers:
 - url: /
 tags:
+- description: requiredAndNullable
+  name: requiredAndNullable
 - description: foo
   name: foo
 - description: upload
@@ -59,6 +61,27 @@ paths:
       - foo
       x-accepts:
       - application/json
+  /requiredAndNullable:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/RequiredAndNullable"
+        description: bodyWithRequiredAndNullableAttributes
+        required: true
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RequiredAndNullable"
+          description: response
+      tags:
+      - requiredAndNullable
+      x-content-type: application/json
+      x-accepts:
+      - application/json
   /upload:
     post:
       requestBody:
@@ -103,6 +126,10 @@ paths:
         style: simple
       responses:
         "200":
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FileContent"
           description: ok
       tags:
       - file
@@ -185,6 +212,62 @@ components:
       required:
       - requiredColor
       - requiredDt
+    RequiredAndNullable:
+      example:
+        str: str
+        file: ""
+        color: red
+        onlyRequired: onlyRequired
+        list:
+        - list
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          format: binary
+          nullable: true
+          type: string
+        color:
+          default: red
+          nullable: true
+          type: string
+        onlyRequired:
+          type: string
+        list:
+          items:
+            type: string
+          nullable: true
+          type: array
+      required:
+      - color
+      - file
+      - list
+      - onlyRequired
+      - str
+      type: object
+    FileContent:
+      example:
+        name: name
+        size: 0
+        virusScan: clean
+      properties:
+        name:
+          readOnly: true
+          type: string
+        size:
+          readOnly: true
+          type: integer
+        virusScan:
+          enum:
+          - clean
+          - detected
+          readOnly: true
+          type: string
+      required:
+      - name
+      type: object
     _upload_post_request:
       properties:
         file:
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileApi.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileApi.md
index 4e6607ae5a71..59683371bc55 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileApi.md
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileApi.md
@@ -10,7 +10,7 @@ All URIs are relative to *http://localhost*
 
 ## fileIdGet
 
-> fileIdGet(id)
+> FileContent fileIdGet(id)
 
 
 
@@ -32,7 +32,8 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -53,7 +54,7 @@ public class Example {
 
 ### Return type
 
-null (empty response body)
+[**FileContent**](FileContent.md)
 
 ### Authorization
 
@@ -62,7 +63,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 
 ### HTTP response details
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileContent.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileContent.md
new file mode 100644
index 000000000000..5b6654a0bf18
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/FileContent.md
@@ -0,0 +1,24 @@
+
+
+# FileContent
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**name** | **String** |  |  [readonly] |
+|**size** | **Integer** |  |  [optional] [readonly] |
+|**virusScan** | [**VirusScanEnum**](#VirusScanEnum) |  |  [optional] [readonly] |
+
+
+
+## Enum: VirusScanEnum
+
+| Name | Value |
+|---- | -----|
+| CLEAN | &quot;clean&quot; |
+| DETECTED | &quot;detected&quot; |
+
+
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
new file mode 100644
index 000000000000..ff4ade0f226d
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
@@ -0,0 +1,17 @@
+
+
+# RequiredAndNullable
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**str** | **String** |  |  |
+|**_file** | **File** |  |  |
+|**color** | **String** |  |  |
+|**onlyRequired** | **String** |  |  |
+|**_list** | **List&lt;String&gt;** |  |  |
+
+
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
new file mode 100644
index 000000000000..ada434bf0b9e
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
@@ -0,0 +1,73 @@
+# RequiredAndNullableApi
+
+All URIs are relative to *http://localhost*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**requiredAndNullablePost**](RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable |  |
+
+
+
+## requiredAndNullablePost
+
+> RequiredAndNullable requiredAndNullablePost(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            RequiredAndNullable result = apiInstance.requiredAndNullablePost(requiredAndNullable);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+[**RequiredAndNullable**](RequiredAndNullable.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
index 4f1bf741d207..a391a80e7577 100644
--- a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
@@ -2,6 +2,7 @@
 
 import org.openapitools.client.ApiClient;
 
+import org.openapitools.client.model.FileContent;
 
 import java.util.HashMap;
 import java.util.List;
@@ -48,6 +49,7 @@ public void setApiClient(ApiClient apiClient) {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
     private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientResponseException {
@@ -66,14 +68,16 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientRespon
         final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<>();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<>();
 
-        final String[] localVarAccepts = { };
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
         final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
         final String[] localVarContentTypes = { };
         final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
 
         String[] localVarAuthNames = new String[] {  };
 
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
         return apiClient.invokeAPI("/file/{id}", HttpMethod.GET, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
     }
 
@@ -82,11 +86,12 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws RestClientRespon
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
-    public void fileIdGet(String id) throws RestClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
-        fileIdGetRequestCreation(id).body(localVarReturnType);
+    public FileContent fileIdGet(String id) throws RestClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return fileIdGetRequestCreation(id).body(localVarReturnType);
     }
 
     /**
@@ -94,10 +99,11 @@ public void fileIdGet(String id) throws RestClientResponseException {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return ResponseEntity&lt;FileContent&gt;
      * @throws RestClientResponseException if an error occurs while attempting to invoke the API
      */
-    public ResponseEntity<Void> fileIdGetWithHttpInfo(String id) throws RestClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<>() {};
+    public ResponseEntity<FileContent> fileIdGetWithHttpInfo(String id) throws RestClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<>() {};
         return fileIdGetRequestCreation(id).toEntity(localVarReturnType);
     }
 
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..cc0e7c9ca9fa
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
@@ -0,0 +1,121 @@
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+
+import org.openapitools.client.model.RequiredAndNullable;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestClient.ResponseSpec;
+import org.springframework.web.client.RestClientResponseException;
+
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullableApi {
+    private ApiClient apiClient;
+
+    public RequiredAndNullableApi() {
+        this(new ApiClient());
+    }
+
+    public RequiredAndNullableApi(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    public ApiClient getApiClient() {
+        return apiClient;
+    }
+
+    public void setApiClient(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    private ResponseSpec requiredAndNullablePostRequestCreation(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        Object postBody = requiredAndNullable;
+        // verify the required parameter 'requiredAndNullable' is set
+        if (requiredAndNullable == null) {
+            throw new RestClientResponseException("Missing the required parameter 'requiredAndNullable' when calling requiredAndNullablePost", HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.getReasonPhrase(), null, null, null);
+        }
+        // create path and map variables
+        final Map<String, Object> pathParams = new HashMap<>();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<>();
+        final HttpHeaders headerParams = new HttpHeaders();
+        final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<>();
+        final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { 
+            "application/json"
+        };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        String[] localVarAuthNames = new String[] {  };
+
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return apiClient.invokeAPI("/requiredAndNullable", HttpMethod.POST, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public RequiredAndNullable requiredAndNullablePost(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).body(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseEntity&lt;RequiredAndNullable&gt;
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).toEntity(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseSpec
+     * @throws RestClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public ResponseSpec requiredAndNullablePostWithResponseSpec(RequiredAndNullable requiredAndNullable) throws RestClientResponseException {
+        return requiredAndNullablePostRequestCreation(requiredAndNullable);
+    }
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
new file mode 100644
index 000000000000..b0f00682525b
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
@@ -0,0 +1,247 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * FileContent
+ */
+@JsonPropertyOrder({
+  FileContent.JSON_PROPERTY_NAME,
+  FileContent.JSON_PROPERTY_SIZE,
+  FileContent.JSON_PROPERTY_VIRUS_SCAN
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+  public static final String JSON_PROPERTY_NAME = "name";
+  
+  private String name;
+
+  public static final String JSON_PROPERTY_SIZE = "size";
+  
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN(String.valueOf("clean")),
+    
+    DETECTED(String.valueOf("detected"));
+
+    private String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_VIRUS_SCAN = "virusScan";
+  
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+  }
+  /**
+   * Constructor with only readonly parameters and all parameters
+   */
+  @JsonCreator
+  public FileContent(
+    @JsonProperty(JSON_PROPERTY_NAME) String name, 
+    @JsonProperty(JSON_PROPERTY_SIZE) Integer size, 
+    @JsonProperty(JSON_PROPERTY_VIRUS_SCAN) VirusScanEnum virusScan
+  ) {
+    this();
+    this.name = name;
+    this.size = size;
+    this.virusScan = virusScan;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_NAME, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getName() {
+    return name;
+  }
+
+
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_SIZE, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_VIRUS_SCAN, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size = size;
+      return this;
+    }
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan = virusScan;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    return new FileContent.Builder()
+      .name(getName())
+      .size(getSize())
+      .virusScan(getVirusScan());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..55653e9e6161
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
@@ -0,0 +1,328 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * RequiredAndNullable
+ */
+@JsonPropertyOrder({
+  RequiredAndNullable.JSON_PROPERTY_STR,
+  RequiredAndNullable.JSON_PROPERTY_FILE,
+  RequiredAndNullable.JSON_PROPERTY_COLOR,
+  RequiredAndNullable.JSON_PROPERTY_ONLY_REQUIRED,
+  RequiredAndNullable.JSON_PROPERTY_LIST
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+  public static final String JSON_PROPERTY_STR = "str";
+  
+  private @Nullable String str;
+
+  public static final String JSON_PROPERTY_FILE = "file";
+  
+  private @Nullable File _file;
+
+  public static final String JSON_PROPERTY_COLOR = "color";
+  
+  private @Nullable String color = "red";
+
+  public static final String JSON_PROPERTY_ONLY_REQUIRED = "onlyRequired";
+  
+  private String onlyRequired;
+
+  public static final String JSON_PROPERTY_LIST = "list";
+  
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() {
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public RequiredAndNullable(@JsonProperty(JSON_PROPERTY_STR) @Nullable String str, @JsonProperty(JSON_PROPERTY_FILE) @Nullable File _file, @JsonProperty(JSON_PROPERTY_COLOR) @Nullable String color, @JsonProperty(JSON_PROPERTY_ONLY_REQUIRED) String onlyRequired, @JsonProperty(JSON_PROPERTY_LIST) @Nullable List<String> _list) {
+    this.str = str;
+    this._file = _file;
+    this.color = color;
+    this.onlyRequired = onlyRequired;
+    this._list = _list;
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getStr() {
+    return str;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable _file(@Nullable File _file) {
+    
+    this._file = _file;
+    return this;
+  }
+
+  /**
+   * Get _file
+   * @return _file
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable File getFile() {
+    return _file;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setFile(@Nullable File _file) {
+    this._file = _file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getColor() {
+    return color;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this._file, requiredAndNullable._file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, _file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    _file: ").append(toIndentedString(_file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str = str;
+      return this;
+    }
+    public RequiredAndNullable.Builder _file(@Nullable File _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color = color;
+      return this;
+    }
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired = onlyRequired;
+      return this;
+    }
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+
+
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable.
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    return new RequiredAndNullable.Builder()
+      .str(getStr())
+      ._file(getFile())
+      .color(getColor())
+      .onlyRequired(getOnlyRequired())
+      ._list(getList());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
new file mode 100644
index 000000000000..41e971ae1aa5
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
@@ -0,0 +1,48 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.model.RequiredAndNullable;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * API tests for RequiredAndNullableApi
+ */
+@Disabled
+public class RequiredAndNullableApiTest {
+
+    private final RequiredAndNullableApi api = new RequiredAndNullableApi();
+
+    
+    /**
+     * 
+     *
+     * 
+     */
+    @Test
+    public void requiredAndNullablePostTest()  {
+        RequiredAndNullable requiredAndNullable = null;
+        RequiredAndNullable response = api.requiredAndNullablePost(requiredAndNullable);
+
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
new file mode 100644
index 000000000000..bc686732b1ca
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
@@ -0,0 +1,55 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for FileContent
+ */
+class FileContentTest {
+    private final FileContent model = new FileContent();
+
+    /**
+     * Model tests for FileContent
+     */
+    @Test
+    void testFileContent() {
+        // TODO: test FileContent
+    }
+
+    /**
+     * Test the property 'name'
+     */
+    @Test
+    void nameTest() {
+        // TODO: test name
+    }
+
+    /**
+     * Test the property 'size'
+     */
+    @Test
+    void sizeTest() {
+        // TODO: test size
+    }
+
+}
diff --git a/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
new file mode 100644
index 000000000000..3d3388460faf
--- /dev/null
+++ b/samples/client/petstore/java/restclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
@@ -0,0 +1,72 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for RequiredAndNullable
+ */
+class RequiredAndNullableTest {
+    private final RequiredAndNullable model = new RequiredAndNullable();
+
+    /**
+     * Model tests for RequiredAndNullable
+     */
+    @Test
+    void testRequiredAndNullable() {
+        // TODO: test RequiredAndNullable
+    }
+
+    /**
+     * Test the property 'str'
+     */
+    @Test
+    void strTest() {
+        // TODO: test str
+    }
+
+    /**
+     * Test the property '_file'
+     */
+    @Test
+    void _fileTest() {
+        // TODO: test _file
+    }
+
+    /**
+     * Test the property 'color'
+     */
+    @Test
+    void colorTest() {
+        // TODO: test color
+    }
+
+    /**
+     * Test the property 'onlyRequired'
+     */
+    @Test
+    void onlyRequiredTest() {
+        // TODO: test onlyRequired
+    }
+
+}
diff --git a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
index d6cab3c6d44e..8dbec199a934 100644
--- a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
+++ b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
@@ -343,7 +343,7 @@ public EnumTest outerEnum(@jakarta.annotation.Nullable OuterEnum outerEnum) {
    * @return outerEnum
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public OuterEnum getOuterEnum() {
diff --git a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
index acaacf9f1ed4..8aee3efd00bc 100644
--- a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
+++ b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
@@ -56,7 +56,7 @@ public HealthCheckResult nullableMessage(@jakarta.annotation.Nullable String nul
    * @return nullableMessage
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getNullableMessage() {
diff --git a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
index fc29bdb28d6c..0d4c5fb23fde 100644
--- a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -122,7 +122,7 @@ public NullableClass integerProp(@jakarta.annotation.Nullable Integer integerPro
    * @return integerProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Integer getIntegerProp() {
@@ -156,7 +156,7 @@ public NullableClass numberProp(@jakarta.annotation.Nullable BigDecimal numberPr
    * @return numberProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public BigDecimal getNumberProp() {
@@ -190,7 +190,7 @@ public NullableClass booleanProp(@jakarta.annotation.Nullable Boolean booleanPro
    * @return booleanProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Boolean getBooleanProp() {
@@ -224,7 +224,7 @@ public NullableClass stringProp(@jakarta.annotation.Nullable String stringProp)
    * @return stringProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getStringProp() {
@@ -258,7 +258,7 @@ public NullableClass dateProp(@jakarta.annotation.Nullable LocalDate dateProp) {
    * @return dateProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public LocalDate getDateProp() {
@@ -292,7 +292,7 @@ public NullableClass datetimeProp(@jakarta.annotation.Nullable OffsetDateTime da
    * @return datetimeProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public OffsetDateTime getDatetimeProp() {
@@ -322,7 +322,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -338,7 +338,7 @@ public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
    * @return arrayNullableProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public List<Object> getArrayNullableProp() {
@@ -368,7 +368,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -384,7 +384,7 @@ public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullab
    * @return arrayAndItemsNullableProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public List<Object> getArrayAndItemsNullableProp() {
@@ -448,7 +448,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -464,7 +464,7 @@ public NullableClass putObjectNullablePropItem(String key, Object objectNullable
    * @return objectNullableProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Map<String, Object> getObjectNullableProp() {
@@ -494,7 +494,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -510,7 +510,7 @@ public NullableClass putObjectAndItemsNullablePropItem(String key, Object object
    * @return objectAndItemsNullableProp
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Map<String, Object> getObjectAndItemsNullableProp() {
diff --git a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
index 504c9fe527a1..cca6f0b72f88 100644
--- a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
+++ b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
@@ -131,7 +131,7 @@ public ParentWithNullable nullableProperty(@jakarta.annotation.Nullable String n
    * @return nullableProperty
    */
   @jakarta.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getNullableProperty() {
diff --git a/samples/client/petstore/java/restclient-useSingleRequestParameter-static/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/restclient-useSingleRequestParameter-static/src/main/java/org/openapitools/client/model/NullableClass.java
index 8e50413b1253..bcb4cde1aa7b 100644
--- a/samples/client/petstore/java/restclient-useSingleRequestParameter-static/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/restclient-useSingleRequestParameter-static/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -315,7 +315,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -360,7 +360,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -438,7 +438,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -483,7 +483,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
index 8e50413b1253..bcb4cde1aa7b 100644
--- a/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -315,7 +315,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -360,7 +360,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -438,7 +438,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -483,7 +483,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/model/NullableClass.java
index 46625c62e002..0b54c6d0fcf5 100644
--- a/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -315,7 +315,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -360,7 +360,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -438,7 +438,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -483,7 +483,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/model/NullableClass.java
index c84494a9487a..e8a4f5eb3b28 100644
--- a/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -362,7 +362,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -440,7 +440,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -485,7 +485,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/.openapi-generator/FILES b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/.openapi-generator/FILES
index 530107e2c6dc..61311fa8a555 100644
--- a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/.openapi-generator/FILES
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/.openapi-generator/FILES
@@ -6,8 +6,11 @@ api/openapi.yaml
 build.gradle
 build.sbt
 docs/FileApi.md
+docs/FileContent.md
 docs/Foo.md
 docs/FooApi.md
+docs/RequiredAndNullable.md
+docs/RequiredAndNullableApi.md
 docs/UploadApi.md
 git_push.sh
 gradle.properties
@@ -28,12 +31,15 @@ src/main/java/org/openapitools/client/ServerConfiguration.java
 src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/api/FileApi.java
 src/main/java/org/openapitools/client/api/FooApi.java
+src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/client/api/UploadApi.java
 src/main/java/org/openapitools/client/api/package-info.java
 src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
 src/main/java/org/openapitools/client/auth/Authentication.java
 src/main/java/org/openapitools/client/auth/HttpBasicAuth.java
 src/main/java/org/openapitools/client/auth/HttpBearerAuth.java
+src/main/java/org/openapitools/client/model/FileContent.java
 src/main/java/org/openapitools/client/model/Foo.java
+src/main/java/org/openapitools/client/model/RequiredAndNullable.java
 src/main/java/org/openapitools/client/model/package-info.java
 src/main/java/org/openapitools/client/package-info.java
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/README.md b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/README.md
index 26aaed664ac5..cc1feadaafbf 100644
--- a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/README.md
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/README.md
@@ -95,7 +95,8 @@ public class FileApiExample {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -116,13 +117,16 @@ Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
 *FileApi* | [**fileIdGet**](docs/FileApi.md#fileIdGet) | **GET** /file/{id} | 
 *FooApi* | [**fooDtParamGet**](docs/FooApi.md#fooDtParamGet) | **GET** /foo/{dtParam} | 
+*RequiredAndNullableApi* | [**requiredAndNullablePost**](docs/RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable | 
 *UploadApi* | [**uploadFilesPost**](docs/UploadApi.md#uploadFilesPost) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadPost**](docs/UploadApi.md#uploadPost) | **POST** /upload | 
 
 
 ## Documentation for Models
 
+ - [FileContent](docs/FileContent.md)
  - [Foo](docs/Foo.md)
+ - [RequiredAndNullable](docs/RequiredAndNullable.md)
 
 
 <a id="documentation-for-authorization"></a>
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/api/openapi.yaml b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/api/openapi.yaml
index b5f967c8460e..15c1f4176a50 100644
--- a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/api/openapi.yaml
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/api/openapi.yaml
@@ -6,6 +6,8 @@ info:
 servers:
 - url: /
 tags:
+- description: requiredAndNullable
+  name: requiredAndNullable
 - description: foo
   name: foo
 - description: upload
@@ -59,6 +61,27 @@ paths:
       - foo
       x-accepts:
       - application/json
+  /requiredAndNullable:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/RequiredAndNullable"
+        description: bodyWithRequiredAndNullableAttributes
+        required: true
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RequiredAndNullable"
+          description: response
+      tags:
+      - requiredAndNullable
+      x-content-type: application/json
+      x-accepts:
+      - application/json
   /upload:
     post:
       requestBody:
@@ -103,6 +126,10 @@ paths:
         style: simple
       responses:
         "200":
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FileContent"
           description: ok
       tags:
       - file
@@ -185,6 +212,62 @@ components:
       required:
       - requiredColor
       - requiredDt
+    RequiredAndNullable:
+      example:
+        str: str
+        file: ""
+        color: red
+        onlyRequired: onlyRequired
+        list:
+        - list
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          format: binary
+          nullable: true
+          type: string
+        color:
+          default: red
+          nullable: true
+          type: string
+        onlyRequired:
+          type: string
+        list:
+          items:
+            type: string
+          nullable: true
+          type: array
+      required:
+      - color
+      - file
+      - list
+      - onlyRequired
+      - str
+      type: object
+    FileContent:
+      example:
+        name: name
+        size: 0
+        virusScan: clean
+      properties:
+        name:
+          readOnly: true
+          type: string
+        size:
+          readOnly: true
+          type: integer
+        virusScan:
+          enum:
+          - clean
+          - detected
+          readOnly: true
+          type: string
+      required:
+      - name
+      type: object
     _upload_post_request:
       properties:
         file:
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileApi.md b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileApi.md
index 4e6607ae5a71..59683371bc55 100644
--- a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileApi.md
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileApi.md
@@ -10,7 +10,7 @@ All URIs are relative to *http://localhost*
 
 ## fileIdGet
 
-> fileIdGet(id)
+> FileContent fileIdGet(id)
 
 
 
@@ -32,7 +32,8 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -53,7 +54,7 @@ public class Example {
 
 ### Return type
 
-null (empty response body)
+[**FileContent**](FileContent.md)
 
 ### Authorization
 
@@ -62,7 +63,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 
 ### HTTP response details
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileContent.md b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileContent.md
new file mode 100644
index 000000000000..5b6654a0bf18
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/FileContent.md
@@ -0,0 +1,24 @@
+
+
+# FileContent
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**name** | **String** |  |  [readonly] |
+|**size** | **Integer** |  |  [optional] [readonly] |
+|**virusScan** | [**VirusScanEnum**](#VirusScanEnum) |  |  [optional] [readonly] |
+
+
+
+## Enum: VirusScanEnum
+
+| Name | Value |
+|---- | -----|
+| CLEAN | &quot;clean&quot; |
+| DETECTED | &quot;detected&quot; |
+
+
+
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
new file mode 100644
index 000000000000..ff4ade0f226d
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
@@ -0,0 +1,17 @@
+
+
+# RequiredAndNullable
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**str** | **String** |  |  |
+|**_file** | **File** |  |  |
+|**color** | **String** |  |  |
+|**onlyRequired** | **String** |  |  |
+|**_list** | **List&lt;String&gt;** |  |  |
+
+
+
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
new file mode 100644
index 000000000000..ada434bf0b9e
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
@@ -0,0 +1,73 @@
+# RequiredAndNullableApi
+
+All URIs are relative to *http://localhost*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**requiredAndNullablePost**](RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable |  |
+
+
+
+## requiredAndNullablePost
+
+> RequiredAndNullable requiredAndNullablePost(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            RequiredAndNullable result = apiInstance.requiredAndNullablePost(requiredAndNullable);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+[**RequiredAndNullable**](RequiredAndNullable.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
index e9d287276f56..56c01021fec5 100644
--- a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
@@ -3,6 +3,7 @@
 import org.openapitools.client.ApiClient;
 import org.openapitools.client.BaseApi;
 
+import org.openapitools.client.model.FileContent;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -41,10 +42,11 @@ public FileApi(ApiClient apiClient) {
      * 
      * <p><b>200</b> - ok
      * @param id  (required)
+     * @return FileContent
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
-    public void fileIdGet(String id) throws RestClientException {
-        fileIdGetWithHttpInfo(id);
+    public FileContent fileIdGet(String id) throws RestClientException {
+        return fileIdGetWithHttpInfo(id).getBody();
     }
 
     /**
@@ -52,10 +54,10 @@ public void fileIdGet(String id) throws RestClientException {
      * 
      * <p><b>200</b> - ok
      * @param id  (required)
-     * @return ResponseEntity&lt;Void&gt;
+     * @return ResponseEntity&lt;FileContent&gt;
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
-    public ResponseEntity<Void> fileIdGetWithHttpInfo(String id) throws RestClientException {
+    public ResponseEntity<FileContent> fileIdGetWithHttpInfo(String id) throws RestClientException {
         Object localVarPostBody = null;
         
         // verify the required parameter 'id' is set
@@ -72,14 +74,16 @@ public ResponseEntity<Void> fileIdGetWithHttpInfo(String id) throws RestClientEx
         final MultiValueMap<String, String> localVarCookieParams = new LinkedMultiValueMap<String, String>();
         final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
 
-        final String[] localVarAccepts = {  };
+        final String[] localVarAccepts = { 
+            "application/json"
+         };
         final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
         final String[] localVarContentTypes = {  };
         final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
 
         String[] localVarAuthNames = new String[] {  };
 
-        ParameterizedTypeReference<Void> localReturnType = new ParameterizedTypeReference<Void>() {};
+        ParameterizedTypeReference<FileContent> localReturnType = new ParameterizedTypeReference<FileContent>() {};
         return apiClient.invokeAPI("/file/{id}", HttpMethod.GET, uriVariables, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localReturnType);
     }
 
@@ -94,7 +98,9 @@ public <T> ResponseEntity<T> invokeAPI(String url, HttpMethod method, Object req
         final MultiValueMap<String, String> localVarCookieParams = new LinkedMultiValueMap<String, String>();
         final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
 
-        final String[] localVarAccepts = {  };
+        final String[] localVarAccepts = { 
+            "application/json"
+         };
         final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
         final String[] localVarContentTypes = {  };
         final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..7778cdd5c5aa
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
@@ -0,0 +1,113 @@
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.BaseApi;
+
+import org.openapitools.client.model.RequiredAndNullable;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestClientException;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullableApi extends BaseApi {
+
+    public RequiredAndNullableApi() {
+        super(new ApiClient());
+    }
+
+    public RequiredAndNullableApi(ApiClient apiClient) {
+        super(apiClient);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+     * @return RequiredAndNullable
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public RequiredAndNullable requiredAndNullablePost(RequiredAndNullable requiredAndNullable) throws RestClientException {
+        return requiredAndNullablePostWithHttpInfo(requiredAndNullable).getBody();
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+     * @return ResponseEntity&lt;RequiredAndNullable&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<RequiredAndNullable> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable) throws RestClientException {
+        Object localVarPostBody = requiredAndNullable;
+        
+        // verify the required parameter 'requiredAndNullable' is set
+        if (requiredAndNullable == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredAndNullable' when calling requiredAndNullablePost");
+        }
+        
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, String> localVarCookieParams = new LinkedMultiValueMap<String, String>();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+         };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { 
+            "application/json"
+         };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        String[] localVarAuthNames = new String[] {  };
+
+        ParameterizedTypeReference<RequiredAndNullable> localReturnType = new ParameterizedTypeReference<RequiredAndNullable>() {};
+        return apiClient.invokeAPI("/requiredAndNullable", HttpMethod.POST, Collections.<String, Object>emptyMap(), localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localReturnType);
+    }
+
+    @Override
+    public <T> ResponseEntity<T> invokeAPI(String url, HttpMethod method, Object request, ParameterizedTypeReference<T> returnType) throws RestClientException {
+        String localVarPath = url.replace(apiClient.getBasePath(), "");
+        Object localVarPostBody = request;
+
+        final Map<String, Object> uriVariables = new HashMap<String, Object>();
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, String> localVarCookieParams = new LinkedMultiValueMap<String, String>();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+         };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { 
+            "application/json"
+         };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        String[] localVarAuthNames = new String[] {  };
+
+        return apiClient.invokeAPI(localVarPath, method, uriVariables, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, returnType);
+    }
+}
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
new file mode 100644
index 000000000000..b0f00682525b
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
@@ -0,0 +1,247 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * FileContent
+ */
+@JsonPropertyOrder({
+  FileContent.JSON_PROPERTY_NAME,
+  FileContent.JSON_PROPERTY_SIZE,
+  FileContent.JSON_PROPERTY_VIRUS_SCAN
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+  public static final String JSON_PROPERTY_NAME = "name";
+  
+  private String name;
+
+  public static final String JSON_PROPERTY_SIZE = "size";
+  
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN(String.valueOf("clean")),
+    
+    DETECTED(String.valueOf("detected"));
+
+    private String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_VIRUS_SCAN = "virusScan";
+  
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+  }
+  /**
+   * Constructor with only readonly parameters and all parameters
+   */
+  @JsonCreator
+  public FileContent(
+    @JsonProperty(JSON_PROPERTY_NAME) String name, 
+    @JsonProperty(JSON_PROPERTY_SIZE) Integer size, 
+    @JsonProperty(JSON_PROPERTY_VIRUS_SCAN) VirusScanEnum virusScan
+  ) {
+    this();
+    this.name = name;
+    this.size = size;
+    this.virusScan = virusScan;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_NAME, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getName() {
+    return name;
+  }
+
+
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_SIZE, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_VIRUS_SCAN, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size = size;
+      return this;
+    }
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan = virusScan;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    return new FileContent.Builder()
+      .name(getName())
+      .size(getSize())
+      .virusScan(getVirusScan());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..55653e9e6161
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
@@ -0,0 +1,328 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+/**
+ * RequiredAndNullable
+ */
+@JsonPropertyOrder({
+  RequiredAndNullable.JSON_PROPERTY_STR,
+  RequiredAndNullable.JSON_PROPERTY_FILE,
+  RequiredAndNullable.JSON_PROPERTY_COLOR,
+  RequiredAndNullable.JSON_PROPERTY_ONLY_REQUIRED,
+  RequiredAndNullable.JSON_PROPERTY_LIST
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+  public static final String JSON_PROPERTY_STR = "str";
+  
+  private @Nullable String str;
+
+  public static final String JSON_PROPERTY_FILE = "file";
+  
+  private @Nullable File _file;
+
+  public static final String JSON_PROPERTY_COLOR = "color";
+  
+  private @Nullable String color = "red";
+
+  public static final String JSON_PROPERTY_ONLY_REQUIRED = "onlyRequired";
+  
+  private String onlyRequired;
+
+  public static final String JSON_PROPERTY_LIST = "list";
+  
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() {
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public RequiredAndNullable(@JsonProperty(JSON_PROPERTY_STR) @Nullable String str, @JsonProperty(JSON_PROPERTY_FILE) @Nullable File _file, @JsonProperty(JSON_PROPERTY_COLOR) @Nullable String color, @JsonProperty(JSON_PROPERTY_ONLY_REQUIRED) String onlyRequired, @JsonProperty(JSON_PROPERTY_LIST) @Nullable List<String> _list) {
+    this.str = str;
+    this._file = _file;
+    this.color = color;
+    this.onlyRequired = onlyRequired;
+    this._list = _list;
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getStr() {
+    return str;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable _file(@Nullable File _file) {
+    
+    this._file = _file;
+    return this;
+  }
+
+  /**
+   * Get _file
+   * @return _file
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable File getFile() {
+    return _file;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setFile(@Nullable File _file) {
+    this._file = _file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getColor() {
+    return color;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this._file, requiredAndNullable._file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, _file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    _file: ").append(toIndentedString(_file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str = str;
+      return this;
+    }
+    public RequiredAndNullable.Builder _file(@Nullable File _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color = color;
+      return this;
+    }
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired = onlyRequired;
+      return this;
+    }
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+
+
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable.
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    return new RequiredAndNullable.Builder()
+      .str(getStr())
+      ._file(getFile())
+      .color(getColor())
+      .onlyRequired(getOnlyRequired())
+      ._list(getList());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
new file mode 100644
index 000000000000..e082ae37e368
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
@@ -0,0 +1,54 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.model.RequiredAndNullable;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+import org.springframework.web.client.RestClientException;
+
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * API tests for RequiredAndNullableApi
+ */
+@Disabled
+class RequiredAndNullableApiTest {
+
+    private final RequiredAndNullableApi api = new RequiredAndNullableApi();
+
+    
+    /**
+     * 
+     *
+     * 
+     *
+     * @throws RestClientException
+     *          if the Api call fails
+     */
+    @Test
+    void requiredAndNullablePostTest() {
+        RequiredAndNullable requiredAndNullable = null;
+
+        RequiredAndNullable response = api.requiredAndNullablePost(requiredAndNullable);
+
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
new file mode 100644
index 000000000000..bc686732b1ca
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
@@ -0,0 +1,55 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for FileContent
+ */
+class FileContentTest {
+    private final FileContent model = new FileContent();
+
+    /**
+     * Model tests for FileContent
+     */
+    @Test
+    void testFileContent() {
+        // TODO: test FileContent
+    }
+
+    /**
+     * Test the property 'name'
+     */
+    @Test
+    void nameTest() {
+        // TODO: test name
+    }
+
+    /**
+     * Test the property 'size'
+     */
+    @Test
+    void sizeTest() {
+        // TODO: test size
+    }
+
+}
diff --git a/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
new file mode 100644
index 000000000000..3d3388460faf
--- /dev/null
+++ b/samples/client/petstore/java/resttemplate-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
@@ -0,0 +1,72 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for RequiredAndNullable
+ */
+class RequiredAndNullableTest {
+    private final RequiredAndNullable model = new RequiredAndNullable();
+
+    /**
+     * Model tests for RequiredAndNullable
+     */
+    @Test
+    void testRequiredAndNullable() {
+        // TODO: test RequiredAndNullable
+    }
+
+    /**
+     * Test the property 'str'
+     */
+    @Test
+    void strTest() {
+        // TODO: test str
+    }
+
+    /**
+     * Test the property '_file'
+     */
+    @Test
+    void _fileTest() {
+        // TODO: test _file
+    }
+
+    /**
+     * Test the property 'color'
+     */
+    @Test
+    void colorTest() {
+        // TODO: test color
+    }
+
+    /**
+     * Test the property 'onlyRequired'
+     */
+    @Test
+    void onlyRequiredTest() {
+        // TODO: test onlyRequired
+    }
+
+}
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/model/NullableClass.java
index 424dfc9afe8e..e0705bb0c852 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -341,7 +341,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -388,7 +388,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -472,7 +472,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -519,7 +519,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/model/NullableClass.java
index 118676eda91d..1dfe7ed13186 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -333,7 +333,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -378,7 +378,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -456,7 +456,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -501,7 +501,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
index c84494a9487a..e8a4f5eb3b28 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -362,7 +362,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -440,7 +440,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -485,7 +485,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/model/NullableClass.java
index c84494a9487a..e8a4f5eb3b28 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -362,7 +362,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -440,7 +440,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -485,7 +485,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/vertx5-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/vertx5-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
index c84494a9487a..e8a4f5eb3b28 100644
--- a/samples/client/petstore/java/vertx5-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/vertx5-supportVertxFuture/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -362,7 +362,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -440,7 +440,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -485,7 +485,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/vertx5/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/vertx5/src/main/java/org/openapitools/client/model/NullableClass.java
index c84494a9487a..e8a4f5eb3b28 100644
--- a/samples/client/petstore/java/vertx5/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/vertx5/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -317,7 +317,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -362,7 +362,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -440,7 +440,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -485,7 +485,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/webclient-jakarta/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/webclient-jakarta/src/main/java/org/openapitools/client/model/NullableClass.java
index d401652b6fa7..de26bea586ab 100644
--- a/samples/client/petstore/java/webclient-jakarta/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/webclient-jakarta/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -314,7 +314,7 @@ public NullableClass arrayNullableProp(@jakarta.annotation.Nullable List<Object>
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -359,7 +359,7 @@ public NullableClass arrayAndItemsNullableProp(@jakarta.annotation.Nullable List
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -437,7 +437,7 @@ public NullableClass objectNullableProp(@jakarta.annotation.Nullable Map<String,
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -482,7 +482,7 @@ public NullableClass objectAndItemsNullableProp(@jakarta.annotation.Nullable Map
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
index 537a17ba9f7d..821db0873c19 100644
--- a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/.openapi-generator/FILES
@@ -6,8 +6,11 @@ api/openapi.yaml
 build.gradle
 build.sbt
 docs/FileApi.md
+docs/FileContent.md
 docs/Foo.md
 docs/FooApi.md
+docs/RequiredAndNullable.md
+docs/RequiredAndNullableApi.md
 docs/UploadApi.md
 git_push.sh
 gradle.properties
@@ -29,12 +32,15 @@ src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/StringUtil.java
 src/main/java/org/openapitools/client/api/FileApi.java
 src/main/java/org/openapitools/client/api/FooApi.java
+src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/client/api/UploadApi.java
 src/main/java/org/openapitools/client/api/package-info.java
 src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
 src/main/java/org/openapitools/client/auth/Authentication.java
 src/main/java/org/openapitools/client/auth/HttpBasicAuth.java
 src/main/java/org/openapitools/client/auth/HttpBearerAuth.java
+src/main/java/org/openapitools/client/model/FileContent.java
 src/main/java/org/openapitools/client/model/Foo.java
+src/main/java/org/openapitools/client/model/RequiredAndNullable.java
 src/main/java/org/openapitools/client/model/package-info.java
 src/main/java/org/openapitools/client/package-info.java
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/README.md b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/README.md
index 36aac7266f67..6e3266ebce3f 100644
--- a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/README.md
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/README.md
@@ -95,7 +95,8 @@ public class FileApiExample {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -116,13 +117,16 @@ Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
 *FileApi* | [**fileIdGet**](docs/FileApi.md#fileIdGet) | **GET** /file/{id} | 
 *FooApi* | [**fooDtParamGet**](docs/FooApi.md#fooDtParamGet) | **GET** /foo/{dtParam} | 
+*RequiredAndNullableApi* | [**requiredAndNullablePost**](docs/RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable | 
 *UploadApi* | [**uploadFilesPost**](docs/UploadApi.md#uploadFilesPost) | **POST** /uploadFiles | 
 *UploadApi* | [**uploadPost**](docs/UploadApi.md#uploadPost) | **POST** /upload | 
 
 
 ## Documentation for Models
 
+ - [FileContent](docs/FileContent.md)
  - [Foo](docs/Foo.md)
+ - [RequiredAndNullable](docs/RequiredAndNullable.md)
 
 
 <a id="documentation-for-authorization"></a>
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/api/openapi.yaml b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/api/openapi.yaml
index b5f967c8460e..15c1f4176a50 100644
--- a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/api/openapi.yaml
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/api/openapi.yaml
@@ -6,6 +6,8 @@ info:
 servers:
 - url: /
 tags:
+- description: requiredAndNullable
+  name: requiredAndNullable
 - description: foo
   name: foo
 - description: upload
@@ -59,6 +61,27 @@ paths:
       - foo
       x-accepts:
       - application/json
+  /requiredAndNullable:
+    post:
+      requestBody:
+        content:
+          application/json:
+            schema:
+              $ref: "#/components/schemas/RequiredAndNullable"
+        description: bodyWithRequiredAndNullableAttributes
+        required: true
+      responses:
+        default:
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/RequiredAndNullable"
+          description: response
+      tags:
+      - requiredAndNullable
+      x-content-type: application/json
+      x-accepts:
+      - application/json
   /upload:
     post:
       requestBody:
@@ -103,6 +126,10 @@ paths:
         style: simple
       responses:
         "200":
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/FileContent"
           description: ok
       tags:
       - file
@@ -185,6 +212,62 @@ components:
       required:
       - requiredColor
       - requiredDt
+    RequiredAndNullable:
+      example:
+        str: str
+        file: ""
+        color: red
+        onlyRequired: onlyRequired
+        list:
+        - list
+        - list
+      properties:
+        str:
+          nullable: true
+          type: string
+        file:
+          format: binary
+          nullable: true
+          type: string
+        color:
+          default: red
+          nullable: true
+          type: string
+        onlyRequired:
+          type: string
+        list:
+          items:
+            type: string
+          nullable: true
+          type: array
+      required:
+      - color
+      - file
+      - list
+      - onlyRequired
+      - str
+      type: object
+    FileContent:
+      example:
+        name: name
+        size: 0
+        virusScan: clean
+      properties:
+        name:
+          readOnly: true
+          type: string
+        size:
+          readOnly: true
+          type: integer
+        virusScan:
+          enum:
+          - clean
+          - detected
+          readOnly: true
+          type: string
+      required:
+      - name
+      type: object
     _upload_post_request:
       properties:
         file:
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileApi.md b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileApi.md
index 4e6607ae5a71..59683371bc55 100644
--- a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileApi.md
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileApi.md
@@ -10,7 +10,7 @@ All URIs are relative to *http://localhost*
 
 ## fileIdGet
 
-> fileIdGet(id)
+> FileContent fileIdGet(id)
 
 
 
@@ -32,7 +32,8 @@ public class Example {
         FileApi apiInstance = new FileApi(defaultClient);
         String id = "id_example"; // String | 
         try {
-            apiInstance.fileIdGet(id);
+            FileContent result = apiInstance.fileIdGet(id);
+            System.out.println(result);
         } catch (ApiException e) {
             System.err.println("Exception when calling FileApi#fileIdGet");
             System.err.println("Status code: " + e.getCode());
@@ -53,7 +54,7 @@ public class Example {
 
 ### Return type
 
-null (empty response body)
+[**FileContent**](FileContent.md)
 
 ### Authorization
 
@@ -62,7 +63,7 @@ No authorization required
 ### HTTP request headers
 
 - **Content-Type**: Not defined
-- **Accept**: Not defined
+- **Accept**: application/json
 
 
 ### HTTP response details
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileContent.md b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileContent.md
new file mode 100644
index 000000000000..5b6654a0bf18
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/FileContent.md
@@ -0,0 +1,24 @@
+
+
+# FileContent
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**name** | **String** |  |  [readonly] |
+|**size** | **Integer** |  |  [optional] [readonly] |
+|**virusScan** | [**VirusScanEnum**](#VirusScanEnum) |  |  [optional] [readonly] |
+
+
+
+## Enum: VirusScanEnum
+
+| Name | Value |
+|---- | -----|
+| CLEAN | &quot;clean&quot; |
+| DETECTED | &quot;detected&quot; |
+
+
+
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
new file mode 100644
index 000000000000..ff4ade0f226d
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullable.md
@@ -0,0 +1,17 @@
+
+
+# RequiredAndNullable
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**str** | **String** |  |  |
+|**_file** | **File** |  |  |
+|**color** | **String** |  |  |
+|**onlyRequired** | **String** |  |  |
+|**_list** | **List&lt;String&gt;** |  |  |
+
+
+
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
new file mode 100644
index 000000000000..ada434bf0b9e
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/docs/RequiredAndNullableApi.md
@@ -0,0 +1,73 @@
+# RequiredAndNullableApi
+
+All URIs are relative to *http://localhost*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**requiredAndNullablePost**](RequiredAndNullableApi.md#requiredAndNullablePost) | **POST** /requiredAndNullable |  |
+
+
+
+## requiredAndNullablePost
+
+> RequiredAndNullable requiredAndNullablePost(requiredAndNullable)
+
+
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.RequiredAndNullableApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost");
+
+        RequiredAndNullableApi apiInstance = new RequiredAndNullableApi(defaultClient);
+        RequiredAndNullable requiredAndNullable = new RequiredAndNullable(); // RequiredAndNullable | bodyWithRequiredAndNullableAttributes
+        try {
+            RequiredAndNullable result = apiInstance.requiredAndNullablePost(requiredAndNullable);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling RequiredAndNullableApi#requiredAndNullablePost");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **requiredAndNullable** | [**RequiredAndNullable**](RequiredAndNullable.md)| bodyWithRequiredAndNullableAttributes | |
+
+### Return type
+
+[**RequiredAndNullable**](RequiredAndNullable.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **0** | response |  -  |
+
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
index 5832d514cbad..5f15e56030a1 100644
--- a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/FileApi.java
@@ -2,6 +2,7 @@
 
 import org.openapitools.client.ApiClient;
 
+import org.openapitools.client.model.FileContent;
 
 import java.util.HashMap;
 import java.util.List;
@@ -50,6 +51,7 @@ public void setApiClient(ApiClient apiClient) {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws WebClientResponseException if an error occurs while attempting to invoke the API
      */
     private ResponseSpec fileIdGetRequestCreation(String id) throws WebClientResponseException {
@@ -68,14 +70,16 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws WebClientRespons
         final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<String, String>();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>();
 
-        final String[] localVarAccepts = { };
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
         final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
         final String[] localVarContentTypes = { };
         final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
 
         String[] localVarAuthNames = new String[] {  };
 
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<Void>() {};
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<FileContent>() {};
         return apiClient.invokeAPI("/file/{id}", HttpMethod.GET, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
     }
 
@@ -84,10 +88,11 @@ private ResponseSpec fileIdGetRequestCreation(String id) throws WebClientRespons
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return FileContent
      * @throws WebClientResponseException if an error occurs while attempting to invoke the API
      */
-    public Mono<Void> fileIdGet(String id) throws WebClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<Void>() {};
+    public Mono<FileContent> fileIdGet(String id) throws WebClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<FileContent>() {};
         return fileIdGetRequestCreation(id).bodyToMono(localVarReturnType);
     }
 
@@ -96,10 +101,11 @@ public Mono<Void> fileIdGet(String id) throws WebClientResponseException {
      * 
      * <p><b>200</b> - ok
      * @param id The id parameter
+     * @return ResponseEntity&lt;FileContent&gt;
      * @throws WebClientResponseException if an error occurs while attempting to invoke the API
      */
-    public Mono<ResponseEntity<Void>> fileIdGetWithHttpInfo(String id) throws WebClientResponseException {
-        ParameterizedTypeReference<Void> localVarReturnType = new ParameterizedTypeReference<Void>() {};
+    public Mono<ResponseEntity<FileContent>> fileIdGetWithHttpInfo(String id) throws WebClientResponseException {
+        ParameterizedTypeReference<FileContent> localVarReturnType = new ParameterizedTypeReference<FileContent>() {};
         return fileIdGetRequestCreation(id).toEntity(localVarReturnType);
     }
 
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..502a694520af
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/api/RequiredAndNullableApi.java
@@ -0,0 +1,123 @@
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+
+import org.openapitools.client.model.RequiredAndNullable;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.stream.Collectors;
+
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.reactive.function.client.WebClient.ResponseSpec;
+import org.springframework.web.reactive.function.client.WebClientResponseException;
+import reactor.core.publisher.Mono;
+import reactor.core.publisher.Flux;
+
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullableApi {
+    private ApiClient apiClient;
+
+    public RequiredAndNullableApi() {
+        this(new ApiClient());
+    }
+
+    public RequiredAndNullableApi(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    public ApiClient getApiClient() {
+        return apiClient;
+    }
+
+    public void setApiClient(ApiClient apiClient) {
+        this.apiClient = apiClient;
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws WebClientResponseException if an error occurs while attempting to invoke the API
+     */
+    private ResponseSpec requiredAndNullablePostRequestCreation(RequiredAndNullable requiredAndNullable) throws WebClientResponseException {
+        Object postBody = requiredAndNullable;
+        // verify the required parameter 'requiredAndNullable' is set
+        if (requiredAndNullable == null) {
+            throw new WebClientResponseException("Missing the required parameter 'requiredAndNullable' when calling requiredAndNullablePost", HttpStatus.BAD_REQUEST.value(), HttpStatus.BAD_REQUEST.getReasonPhrase(), null, null, null);
+        }
+        // create path and map variables
+        final Map<String, Object> pathParams = new HashMap<String, Object>();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders headerParams = new HttpHeaders();
+        final MultiValueMap<String, String> cookieParams = new LinkedMultiValueMap<String, String>();
+        final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { 
+            "application/json"
+        };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        String[] localVarAuthNames = new String[] {  };
+
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<RequiredAndNullable>() {};
+        return apiClient.invokeAPI("/requiredAndNullable", HttpMethod.POST, pathParams, localVarQueryParams, postBody, headerParams, cookieParams, formParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return RequiredAndNullable
+     * @throws WebClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public Mono<RequiredAndNullable> requiredAndNullablePost(RequiredAndNullable requiredAndNullable) throws WebClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<RequiredAndNullable>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).bodyToMono(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseEntity&lt;RequiredAndNullable&gt;
+     * @throws WebClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public Mono<ResponseEntity<RequiredAndNullable>> requiredAndNullablePostWithHttpInfo(RequiredAndNullable requiredAndNullable) throws WebClientResponseException {
+        ParameterizedTypeReference<RequiredAndNullable> localVarReturnType = new ParameterizedTypeReference<RequiredAndNullable>() {};
+        return requiredAndNullablePostRequestCreation(requiredAndNullable).toEntity(localVarReturnType);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>0</b> - response
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes
+     * @return ResponseSpec
+     * @throws WebClientResponseException if an error occurs while attempting to invoke the API
+     */
+    public ResponseSpec requiredAndNullablePostWithResponseSpec(RequiredAndNullable requiredAndNullable) throws WebClientResponseException {
+        return requiredAndNullablePostRequestCreation(requiredAndNullable);
+    }
+}
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
new file mode 100644
index 000000000000..f93380d95eac
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/FileContent.java
@@ -0,0 +1,246 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+/**
+ * FileContent
+ */
+@JsonPropertyOrder({
+  FileContent.JSON_PROPERTY_NAME,
+  FileContent.JSON_PROPERTY_SIZE,
+  FileContent.JSON_PROPERTY_VIRUS_SCAN
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+  public static final String JSON_PROPERTY_NAME = "name";
+  
+  private String name;
+
+  public static final String JSON_PROPERTY_SIZE = "size";
+  
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN(String.valueOf("clean")),
+    
+    DETECTED(String.valueOf("detected"));
+
+    private String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_VIRUS_SCAN = "virusScan";
+  
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+  }
+  /**
+   * Constructor with only readonly parameters and all parameters
+   */
+  @JsonCreator
+  public FileContent(
+    @JsonProperty(JSON_PROPERTY_NAME) String name, 
+    @JsonProperty(JSON_PROPERTY_SIZE) Integer size, 
+    @JsonProperty(JSON_PROPERTY_VIRUS_SCAN) VirusScanEnum virusScan
+  ) {
+    this();
+    this.name = name;
+    this.size = size;
+    this.virusScan = virusScan;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_NAME, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getName() {
+    return name;
+  }
+
+
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_SIZE, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_VIRUS_SCAN, required = false)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size = size;
+      return this;
+    }
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan = virusScan;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    return new FileContent.Builder()
+      .name(getName())
+      .size(getSize())
+      .virusScan(getVirusScan());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..9c18ec5777e1
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/main/java/org/openapitools/client/model/RequiredAndNullable.java
@@ -0,0 +1,327 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+/**
+ * RequiredAndNullable
+ */
+@JsonPropertyOrder({
+  RequiredAndNullable.JSON_PROPERTY_STR,
+  RequiredAndNullable.JSON_PROPERTY_FILE,
+  RequiredAndNullable.JSON_PROPERTY_COLOR,
+  RequiredAndNullable.JSON_PROPERTY_ONLY_REQUIRED,
+  RequiredAndNullable.JSON_PROPERTY_LIST
+})
+@jakarta.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+  public static final String JSON_PROPERTY_STR = "str";
+  
+  private @Nullable String str;
+
+  public static final String JSON_PROPERTY_FILE = "file";
+  
+  private @Nullable File _file;
+
+  public static final String JSON_PROPERTY_COLOR = "color";
+  
+  private @Nullable String color = "red";
+
+  public static final String JSON_PROPERTY_ONLY_REQUIRED = "onlyRequired";
+  
+  private String onlyRequired;
+
+  public static final String JSON_PROPERTY_LIST = "list";
+  
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() {
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public RequiredAndNullable(@JsonProperty(JSON_PROPERTY_STR) @Nullable String str, @JsonProperty(JSON_PROPERTY_FILE) @Nullable File _file, @JsonProperty(JSON_PROPERTY_COLOR) @Nullable String color, @JsonProperty(JSON_PROPERTY_ONLY_REQUIRED) String onlyRequired, @JsonProperty(JSON_PROPERTY_LIST) @Nullable List<String> _list) {
+    this.str = str;
+    this._file = _file;
+    this.color = color;
+    this.onlyRequired = onlyRequired;
+    this._list = _list;
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getStr() {
+    return str;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_STR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable _file(@Nullable File _file) {
+    
+    this._file = _file;
+    return this;
+  }
+
+  /**
+   * Get _file
+   * @return _file
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable File getFile() {
+    return _file;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_FILE, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setFile(@Nullable File _file) {
+    this._file = _file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable String getColor() {
+    return color;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_COLOR, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_ONLY_REQUIRED, required = true)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+
+  @JsonProperty(value = JSON_PROPERTY_LIST, required = false)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this._file, requiredAndNullable._file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, _file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    _file: ").append(toIndentedString(_file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str = str;
+      return this;
+    }
+    public RequiredAndNullable.Builder _file(@Nullable File _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color = color;
+      return this;
+    }
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired = onlyRequired;
+      return this;
+    }
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+
+
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable.
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    return new RequiredAndNullable.Builder()
+      .str(getStr())
+      ._file(getFile())
+      .color(getColor())
+      .onlyRequired(getOnlyRequired())
+      ._list(getList());
+  }
+
+
+}
+
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
new file mode 100644
index 000000000000..5adf56d29694
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/api/RequiredAndNullableApiTest.java
@@ -0,0 +1,50 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.model.RequiredAndNullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * API tests for RequiredAndNullableApi
+ */
+@Disabled
+public class RequiredAndNullableApiTest {
+
+    private final RequiredAndNullableApi api = new RequiredAndNullableApi();
+
+    
+    /**
+     * 
+     *
+     * 
+     */
+    @Test
+    public void requiredAndNullablePostTest()  {
+        // uncomment below to test the function
+        //RequiredAndNullable requiredAndNullable = null;
+        //RequiredAndNullable response = api.requiredAndNullablePost(requiredAndNullable).block();
+
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
new file mode 100644
index 000000000000..bc686732b1ca
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/FileContentTest.java
@@ -0,0 +1,55 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for FileContent
+ */
+class FileContentTest {
+    private final FileContent model = new FileContent();
+
+    /**
+     * Model tests for FileContent
+     */
+    @Test
+    void testFileContent() {
+        // TODO: test FileContent
+    }
+
+    /**
+     * Test the property 'name'
+     */
+    @Test
+    void nameTest() {
+        // TODO: test name
+    }
+
+    /**
+     * Test the property 'size'
+     */
+    @Test
+    void sizeTest() {
+        // TODO: test size
+    }
+
+}
diff --git a/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
new file mode 100644
index 000000000000..3d3388460faf
--- /dev/null
+++ b/samples/client/petstore/java/webclient-springBoot4-jackson3-jspecify/src/test/java/org/openapitools/client/model/RequiredAndNullableTest.java
@@ -0,0 +1,72 @@
+/*
+ * jspecify
+ * test fully qualified name and jspecify
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.io.File;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Model tests for RequiredAndNullable
+ */
+class RequiredAndNullableTest {
+    private final RequiredAndNullable model = new RequiredAndNullable();
+
+    /**
+     * Model tests for RequiredAndNullable
+     */
+    @Test
+    void testRequiredAndNullable() {
+        // TODO: test RequiredAndNullable
+    }
+
+    /**
+     * Test the property 'str'
+     */
+    @Test
+    void strTest() {
+        // TODO: test str
+    }
+
+    /**
+     * Test the property '_file'
+     */
+    @Test
+    void _fileTest() {
+        // TODO: test _file
+    }
+
+    /**
+     * Test the property 'color'
+     */
+    @Test
+    void colorTest() {
+        // TODO: test color
+    }
+
+    /**
+     * Test the property 'onlyRequired'
+     */
+    @Test
+    void onlyRequiredTest() {
+        // TODO: test onlyRequired
+    }
+
+}
diff --git a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
index 4cb6c72d1c7a..a2abc60038f5 100644
--- a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
+++ b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/EnumTest.java
@@ -342,7 +342,7 @@ public EnumTest outerEnum(@javax.annotation.Nullable OuterEnum outerEnum) {
    * @return outerEnum
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public OuterEnum getOuterEnum() {
diff --git a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
index fd3b4c322384..3acd36551d5c 100644
--- a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
+++ b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/HealthCheckResult.java
@@ -55,7 +55,7 @@ public HealthCheckResult nullableMessage(@javax.annotation.Nullable String nulla
    * @return nullableMessage
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getNullableMessage() {
diff --git a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
index de20b627ec8a..e33c593549c5 100644
--- a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -121,7 +121,7 @@ public NullableClass integerProp(@javax.annotation.Nullable Integer integerProp)
    * @return integerProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Integer getIntegerProp() {
@@ -155,7 +155,7 @@ public NullableClass numberProp(@javax.annotation.Nullable BigDecimal numberProp
    * @return numberProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public BigDecimal getNumberProp() {
@@ -189,7 +189,7 @@ public NullableClass booleanProp(@javax.annotation.Nullable Boolean booleanProp)
    * @return booleanProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Boolean getBooleanProp() {
@@ -223,7 +223,7 @@ public NullableClass stringProp(@javax.annotation.Nullable String stringProp) {
    * @return stringProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getStringProp() {
@@ -257,7 +257,7 @@ public NullableClass dateProp(@javax.annotation.Nullable LocalDate dateProp) {
    * @return dateProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public LocalDate getDateProp() {
@@ -291,7 +291,7 @@ public NullableClass datetimeProp(@javax.annotation.Nullable OffsetDateTime date
    * @return datetimeProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public OffsetDateTime getDatetimeProp() {
@@ -321,7 +321,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -337,7 +337,7 @@ public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
    * @return arrayNullableProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public List<Object> getArrayNullableProp() {
@@ -367,7 +367,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -383,7 +383,7 @@ public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullab
    * @return arrayAndItemsNullableProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public List<Object> getArrayAndItemsNullableProp() {
@@ -447,7 +447,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -463,7 +463,7 @@ public NullableClass putObjectNullablePropItem(String key, Object objectNullable
    * @return objectNullableProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Map<String, Object> getObjectNullableProp() {
@@ -493,7 +493,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -509,7 +509,7 @@ public NullableClass putObjectAndItemsNullablePropItem(String key, Object object
    * @return objectAndItemsNullableProp
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public Map<String, Object> getObjectAndItemsNullableProp() {
diff --git a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
index 25f57e937f87..988db24f6d00 100644
--- a/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
+++ b/samples/client/petstore/java/webclient-swagger2/src/main/java/org/openapitools/client/model/ParentWithNullable.java
@@ -130,7 +130,7 @@ public ParentWithNullable nullableProperty(@javax.annotation.Nullable String nul
    * @return nullableProperty
    */
   @javax.annotation.Nullable
-  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "")
+  @Schema(requiredMode = Schema.RequiredMode.NOT_REQUIRED, description = "", nullable = true)
   @JsonIgnore
 
   public String getNullableProperty() {
diff --git a/samples/client/petstore/java/webclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/webclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
index de1623f94d5d..d043d63cd0db 100644
--- a/samples/client/petstore/java/webclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/webclient-useSingleRequestParameter/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -314,7 +314,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -359,7 +359,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -437,7 +437,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -482,7 +482,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/NullableClass.java
index ecc0197fc121..8229f317c5a9 100644
--- a/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -314,7 +314,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -359,7 +359,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -437,7 +437,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -482,7 +482,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/client/petstore/spring-cloud-deprecated/src/main/java/org/openapitools/model/Pet.java b/samples/client/petstore/spring-cloud-deprecated/src/main/java/org/openapitools/model/Pet.java
index 53b64044c6e3..cbfefe49d0ce 100644
--- a/samples/client/petstore/spring-cloud-deprecated/src/main/java/org/openapitools/model/Pet.java
+++ b/samples/client/petstore/spring-cloud-deprecated/src/main/java/org/openapitools/model/Pet.java
@@ -149,8 +149,8 @@ public Pet name(String name) {
    * Get name
    * @return name
    */
-  @NotNull 
-  @Schema(name = "name", example = "doggie", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "name", example = "doggie", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("name")
   public JsonNullable<String> getName() {
     return name;
diff --git a/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index d88271c2bf46..bff7e7b1bf37 100644
--- a/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -49,7 +49,7 @@ public ContainerDefaultValueDto nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -76,7 +76,7 @@ public ContainerDefaultValueDto nullableRequiredArray(List<String> nullableRequi
   }
 
   public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -87,7 +87,7 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
+  /* @Present */ 
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -132,7 +132,7 @@ public ContainerDefaultValueDto nullableArrayWithDefault(List<String> nullableAr
   }
 
   public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/NullableMapPropertyDto.java b/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
index f84d9d21f9cf..9014b6f011cb 100644
--- a/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
+++ b/samples/client/petstore/spring-http-interface-bean-validation/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
@@ -36,7 +36,7 @@ public NullableMapPropertyDto languageValues(Map<String, String> languageValues)
   }
 
   public NullableMapPropertyDto putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index fe0be24e229d..97abe298e2a2 100644
--- a/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -48,7 +48,7 @@ public ContainerDefaultValueDto nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -75,7 +75,7 @@ public ContainerDefaultValueDto nullableRequiredArray(List<String> nullableRequi
   }
 
   public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -86,7 +86,7 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull
+  /* @Present */
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -131,7 +131,7 @@ public ContainerDefaultValueDto nullableArrayWithDefault(List<String> nullableAr
   }
 
   public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/NullableMapPropertyDto.java b/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
index d9edf72050f1..4e174dcc657b 100644
--- a/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
+++ b/samples/client/petstore/spring-http-interface-noResponseEntity/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
@@ -35,7 +35,7 @@ public NullableMapPropertyDto languageValues(Map<String, String> languageValues)
   }
 
   public NullableMapPropertyDto putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index ca932fee5f0f..e01eaa250b71 100644
--- a/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -55,7 +55,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -82,7 +82,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -93,7 +93,7 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
+  /* @Present */ 
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -138,7 +138,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
index dff5aa4523f8..591056e5100f 100644
--- a/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/client/petstore/spring-http-interface-reactive-bean-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -34,7 +34,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 31a8133cb94f..d0b2e33d0b77 100644
--- a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -54,7 +54,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -81,7 +81,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -92,7 +92,7 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull
+  /* @Present */
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -137,7 +137,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
index 5e0395f3fd34..a723c91d0d1c 100644
--- a/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/client/petstore/spring-http-interface-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -33,7 +33,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 31a8133cb94f..d0b2e33d0b77 100644
--- a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -54,7 +54,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -81,7 +81,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -92,7 +92,7 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull
+  /* @Present */
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -137,7 +137,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
index 5e0395f3fd34..a723c91d0d1c 100644
--- a/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/client/petstore/spring-http-interface-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -33,7 +33,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface-springboot-4/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/client/petstore/spring-http-interface-springboot-4/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index b5627e929b6b..fd7d122ed37b 100644
--- a/samples/client/petstore/spring-http-interface-springboot-4/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/client/petstore/spring-http-interface-springboot-4/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -86,7 +86,7 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
+  
   @JsonProperty("nullable_required_array")
   public List<String> getNullableRequiredArray() {
     return nullableRequiredArray;
diff --git a/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 219aeb0cd0ed..0876fa4f8b1f 100644
--- a/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -83,7 +83,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -94,7 +94,7 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
+  /* @Present */ 
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -139,7 +139,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/NullableMapProperty.java
index c25a2eaa55bf..77672ce2ef4f 100644
--- a/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/client/petstore/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfigurator/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index fe0be24e229d..97abe298e2a2 100644
--- a/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -48,7 +48,7 @@ public ContainerDefaultValueDto nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -75,7 +75,7 @@ public ContainerDefaultValueDto nullableRequiredArray(List<String> nullableRequi
   }
 
   public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -86,7 +86,7 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull
+  /* @Present */
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -131,7 +131,7 @@ public ContainerDefaultValueDto nullableArrayWithDefault(List<String> nullableAr
   }
 
   public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
diff --git a/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/NullableMapPropertyDto.java b/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
index d9edf72050f1..4e174dcc657b 100644
--- a/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
+++ b/samples/client/petstore/spring-http-interface/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
@@ -35,7 +35,7 @@ public NullableMapPropertyDto languageValues(Map<String, String> languageValues)
   }
 
   public NullableMapPropertyDto putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableClass.java
index 84830c15f4a2..b24140ddb017 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -307,7 +307,7 @@ public NullableClass arrayNullableProp(@javax.annotation.Nullable List<Object> a
   }
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -352,7 +352,7 @@ public NullableClass arrayAndItemsNullableProp(@javax.annotation.Nullable List<O
   }
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
     }
     try {
@@ -430,7 +430,7 @@ public NullableClass objectNullableProp(@javax.annotation.Nullable Map<String, O
   }
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
@@ -475,7 +475,7 @@ public NullableClass objectAndItemsNullableProp(@javax.annotation.Nullable Map<S
   }
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
     }
     try {
diff --git a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 5e934e643224..8caad40bef04 100644
--- a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -48,7 +48,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -60,7 +60,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -76,7 +76,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -87,8 +87,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -134,7 +134,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -146,7 +146,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/openapi3/client/petstore/spring-cloud-oas3-fakeapi/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/.openapi-generator/FILES b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/.openapi-generator/FILES
index bc1941bdad50..559ef9c95db3 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/.openapi-generator/FILES
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/.openapi-generator/FILES
@@ -3,8 +3,11 @@ pom.xml
 src/main/java/org/openapitools/api/ApiUtil.java
 src/main/java/org/openapitools/api/FileApi.java
 src/main/java/org/openapitools/api/FooApi.java
+src/main/java/org/openapitools/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/api/UploadApi.java
 src/main/java/org/openapitools/api/UploadFilesApi.java
 src/main/java/org/openapitools/api/package-info.java
+src/main/java/org/openapitools/model/FileContent.java
 src/main/java/org/openapitools/model/Foo.java
+src/main/java/org/openapitools/model/RequiredAndNullable.java
 src/main/java/org/openapitools/model/package-info.java
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/FileApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/FileApi.java
index 0ee298fc93e5..ee8c018556a2 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/FileApi.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/FileApi.java
@@ -5,6 +5,7 @@
  */
 package org.openapitools.api;
 
+import org.openapitools.model.FileContent;
 import io.swagger.v3.oas.annotations.ExternalDocumentation;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
@@ -52,16 +53,28 @@ default Optional<NativeWebRequest> getRequest() {
         operationId = "fileIdGet",
         tags = { "file" },
         responses = {
-            @ApiResponse(responseCode = "200", description = "ok")
+            @ApiResponse(responseCode = "200", description = "ok", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = FileContent.class))
+            })
         }
     )
     @RequestMapping(
         method = RequestMethod.GET,
-        value = FileApi.PATH_FILE_ID_GET
+        value = FileApi.PATH_FILE_ID_GET,
+        produces = { "application/json" }
     )
-    default ResponseEntity<Void> fileIdGet(
+    default ResponseEntity<FileContent> fileIdGet(
         @Parameter(name = "id", description = "", required = true, in = ParameterIn.PATH) @PathVariable("id") String id
     ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"name\" : \"name\", \"size\" : 0, \"virusScan\" : \"clean\" }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/RequiredAndNullableApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..a7057ce15f82
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
@@ -0,0 +1,83 @@
+/*
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (7.25.0-SNAPSHOT).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+package org.openapitools.api;
+
+import org.openapitools.model.RequiredAndNullable;
+import io.swagger.v3.oas.annotations.ExternalDocumentation;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.Parameters;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import io.swagger.v3.oas.annotations.enums.ParameterIn;
+import io.swagger.v3.oas.annotations.media.ExampleObject;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.multipart.MultipartFile;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import jakarta.annotation.Generated;
+
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+@Validated
+@Tag(name = "requiredAndNullable", description = "requiredAndNullable")
+public interface RequiredAndNullableApi {
+
+    default Optional<NativeWebRequest> getRequest() {
+        return Optional.empty();
+    }
+
+    String PATH_REQUIRED_AND_NULLABLE_POST = "/requiredAndNullable";
+    /**
+     * POST /requiredAndNullable
+     *
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+     * @return response (status code 200)
+     */
+    @Operation(
+        operationId = "requiredAndNullablePost",
+        tags = { "requiredAndNullable" },
+        responses = {
+            @ApiResponse(responseCode = "default", description = "response", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = RequiredAndNullable.class))
+            })
+        }
+    )
+    @RequestMapping(
+        method = RequestMethod.POST,
+        value = RequiredAndNullableApi.PATH_REQUIRED_AND_NULLABLE_POST,
+        produces = { "application/json" },
+        consumes = { "application/json" }
+    )
+    default ResponseEntity<RequiredAndNullable> requiredAndNullablePost(
+        @Parameter(name = "RequiredAndNullable", description = "bodyWithRequiredAndNullableAttributes", required = true) @Valid @RequestBody RequiredAndNullable requiredAndNullable
+    ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"str\" : \"str\", \"file\" : \"\", \"color\" : \"red\", \"onlyRequired\" : \"onlyRequired\", \"list\" : [ \"list\", \"list\" ] }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
+        return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
+
+    }
+
+}
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/FileContent.java b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/FileContent.java
new file mode 100644
index 000000000000..02f2fd5666ed
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/FileContent.java
@@ -0,0 +1,274 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.openapitools.jackson.nullable.JsonNullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * FileContent
+ */
+
+@JacksonXmlRootElement(localName = "FileContent")
+@XmlRootElement(name = "FileContent")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+
+  private String name;
+
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN("clean"),
+    
+    DETECTED("detected");
+
+    private final String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters
+   */
+  public FileContent(String name) {
+    this.name = name;
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public FileContent(String name, @Nullable Integer size, @Nullable VirusScanEnum virusScan) {
+      this.name = name;
+      this.size = size;
+      this.virusScan = virusScan;
+  }
+
+  public FileContent name(String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @Schema(name = "name", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  @XmlElement(name = "name")
+  public String getName() {
+    return name;
+  }
+
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public FileContent size(@Nullable Integer size) {
+    this.size = size;
+    return this;
+  }
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @Schema(name = "size", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  @XmlElement(name = "size")
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  public void setSize(@Nullable Integer size) {
+    this.size = size;
+  }
+
+  public FileContent virusScan(@Nullable VirusScanEnum virusScan) {
+    this.virusScan = virusScan;
+    return this;
+  }
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @Schema(name = "virusScan", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  @XmlElement(name = "virusScan")
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  public void setVirusScan(@Nullable VirusScanEnum virusScan) {
+    this.virusScan = virusScan;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(FileContent value) { 
+      this.instance.setName(value.name);
+      this.instance.setSize(value.size);
+      this.instance.setVirusScan(value.virusScan);
+      return this;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name(name);
+      return this;
+    }
+    
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size(size);
+      return this;
+    }
+    
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan(virusScan);
+      return this;
+    }
+    
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    FileContent.Builder builder = new FileContent.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/Foo.java b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/Foo.java
index 59f585f6eb8d..edae969af681 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/Foo.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/Foo.java
@@ -131,7 +131,7 @@ public Foo nullableDt(java.time.@Nullable Instant nullableDt) {
    * @return nullableDt
    */
   @Valid 
-  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableDt")
   @JacksonXmlProperty(localName = "nullableDt")
   @XmlElement(name = "nullableDt")
@@ -177,7 +177,7 @@ public Foo nullableBinary(org.springframework.core.io.@Nullable Resource nullabl
    * @return nullableBinary
    */
   @Valid 
-  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableBinary")
   @JacksonXmlProperty(localName = "nullableBinary")
   @XmlElement(name = "nullableBinary")
@@ -263,7 +263,7 @@ public Foo nullableListMinIntems(@Nullable List<java.time.Instant> nullableListM
   }
 
   public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsItem) {
-    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent()) {
+    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent() || this.nullableListMinIntems.get() == null) {
       this.nullableListMinIntems = JsonNullable.of(new ArrayList<>());
     }
     this.nullableListMinIntems.get().add(nullableListMinIntemsItem);
@@ -275,7 +275,7 @@ public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsI
    * @return nullableListMinIntems
    */
   @Valid @Size(min = 1) 
-  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableListMinIntems")
   @JacksonXmlProperty(localName = "nullableListMinIntems")
   @JacksonXmlElementWrapper(useWrapping = false)
@@ -346,7 +346,7 @@ public Foo nullableNumber(java.math.@Nullable BigDecimal nullableNumber) {
    * @return nullableNumber
    */
   @Valid 
-  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableNumber")
   @JacksonXmlProperty(localName = "nullableNumber")
   @XmlElement(name = "nullableNumber")
@@ -416,7 +416,7 @@ public Foo nullableColor(@Nullable String nullableColor) {
    * @return nullableColor
    */
   
-  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableColor")
   @JacksonXmlProperty(localName = "nullableColor")
   @XmlElement(name = "nullableColor")
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/RequiredAndNullable.java b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..3db95fb22627
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-openapiNullable/src/main/java/org/openapitools/model/RequiredAndNullable.java
@@ -0,0 +1,334 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import org.openapitools.jackson.nullable.JsonNullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * RequiredAndNullable
+ */
+
+@JacksonXmlRootElement(localName = "RequiredAndNullable")
+@XmlRootElement(name = "RequiredAndNullable")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+
+  private JsonNullable<String> str = JsonNullable.<String>undefined();
+
+  private JsonNullable<org.springframework.core.io.Resource> file = JsonNullable.<org.springframework.core.io.Resource>undefined();
+
+  private JsonNullable<String> color = JsonNullable.<String>undefined();
+
+  private String onlyRequired;
+
+  private JsonNullable<List<String>> _list = JsonNullable.<List<String>>undefined();
+
+  public RequiredAndNullable() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters and all parameters
+   */
+  public RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list) {
+    this.str = JsonNullable.of(str);
+    this.file = JsonNullable.of(file);
+    this.color = JsonNullable.of(color);
+    this.onlyRequired = onlyRequired;
+    this._list = JsonNullable.of(_list);
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    this.str = JsonNullable.of(str);
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  /* @Present */ 
+  @Schema(name = "str", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  @XmlElement(name = "str")
+  public JsonNullable<String> getStr() {
+    return str;
+  }
+
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  public void setStr(JsonNullable<String> str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable file(org.springframework.core.io.@Nullable Resource file) {
+    this.file = JsonNullable.of(file);
+    return this;
+  }
+
+  /**
+   * Get file
+   * @return file
+   */
+  /* @Present */ @Valid 
+  @Schema(name = "file", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  @XmlElement(name = "file")
+  public JsonNullable<org.springframework.core.io.Resource> getFile() {
+    return file;
+  }
+
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  public void setFile(JsonNullable<org.springframework.core.io.Resource> file) {
+    this.file = file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    this.color = JsonNullable.of(color);
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  /* @Present */ 
+  @Schema(name = "color", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  @XmlElement(name = "color")
+  public JsonNullable<String> getColor() {
+    return color;
+  }
+
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  public void setColor(JsonNullable<String> color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  @NotNull 
+  @Schema(name = "onlyRequired", requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  @XmlElement(name = "onlyRequired")
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    this._list = JsonNullable.of(_list);
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null || !this._list.isPresent() || this._list.get() == null) {
+      this._list = JsonNullable.of(new ArrayList<>());
+    }
+    this._list.get().add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  /* @Present */ 
+  @Schema(name = "list", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  @XmlElement(name = "list")
+  public JsonNullable<List<String>> getList() {
+    return _list;
+  }
+
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  public void setList(JsonNullable<List<String>> _list) {
+    this._list = _list;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this.file, requiredAndNullable.file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    file: ").append(toIndentedString(file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(RequiredAndNullable value) { 
+      this.instance.setStr(value.str);
+      this.instance.setFile(value.file);
+      this.instance.setColor(value.color);
+      this.instance.setOnlyRequired(value.onlyRequired);
+      this.instance.setList(value._list);
+      return this;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str(str);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder str(JsonNullable<String> str) {
+      this.instance.str = str;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder file(org.springframework.core.io.@Nullable Resource file) {
+      this.instance.file(file);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder file(JsonNullable<org.springframework.core.io.Resource> file) {
+      this.instance.file = file;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color(color);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder color(JsonNullable<String> color) {
+      this.instance.color = color;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired(onlyRequired);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list(_list);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder _list(JsonNullable<List<String>> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+    
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    RequiredAndNullable.Builder builder = new RequiredAndNullable.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/.openapi-generator/FILES b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/.openapi-generator/FILES
index bc1941bdad50..559ef9c95db3 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/.openapi-generator/FILES
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/.openapi-generator/FILES
@@ -3,8 +3,11 @@ pom.xml
 src/main/java/org/openapitools/api/ApiUtil.java
 src/main/java/org/openapitools/api/FileApi.java
 src/main/java/org/openapitools/api/FooApi.java
+src/main/java/org/openapitools/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/api/UploadApi.java
 src/main/java/org/openapitools/api/UploadFilesApi.java
 src/main/java/org/openapitools/api/package-info.java
+src/main/java/org/openapitools/model/FileContent.java
 src/main/java/org/openapitools/model/Foo.java
+src/main/java/org/openapitools/model/RequiredAndNullable.java
 src/main/java/org/openapitools/model/package-info.java
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/FileApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/FileApi.java
index 0ee298fc93e5..ee8c018556a2 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/FileApi.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/FileApi.java
@@ -5,6 +5,7 @@
  */
 package org.openapitools.api;
 
+import org.openapitools.model.FileContent;
 import io.swagger.v3.oas.annotations.ExternalDocumentation;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
@@ -52,16 +53,28 @@ default Optional<NativeWebRequest> getRequest() {
         operationId = "fileIdGet",
         tags = { "file" },
         responses = {
-            @ApiResponse(responseCode = "200", description = "ok")
+            @ApiResponse(responseCode = "200", description = "ok", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = FileContent.class))
+            })
         }
     )
     @RequestMapping(
         method = RequestMethod.GET,
-        value = FileApi.PATH_FILE_ID_GET
+        value = FileApi.PATH_FILE_ID_GET,
+        produces = { "application/json" }
     )
-    default ResponseEntity<Void> fileIdGet(
+    default ResponseEntity<FileContent> fileIdGet(
         @Parameter(name = "id", description = "", required = true, in = ParameterIn.PATH) @PathVariable("id") String id
     ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"name\" : \"name\", \"size\" : 0, \"virusScan\" : \"clean\" }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/RequiredAndNullableApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..a7057ce15f82
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
@@ -0,0 +1,83 @@
+/*
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (7.25.0-SNAPSHOT).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+package org.openapitools.api;
+
+import org.openapitools.model.RequiredAndNullable;
+import io.swagger.v3.oas.annotations.ExternalDocumentation;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.Parameters;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import io.swagger.v3.oas.annotations.enums.ParameterIn;
+import io.swagger.v3.oas.annotations.media.ExampleObject;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.multipart.MultipartFile;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import jakarta.annotation.Generated;
+
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+@Validated
+@Tag(name = "requiredAndNullable", description = "requiredAndNullable")
+public interface RequiredAndNullableApi {
+
+    default Optional<NativeWebRequest> getRequest() {
+        return Optional.empty();
+    }
+
+    String PATH_REQUIRED_AND_NULLABLE_POST = "/requiredAndNullable";
+    /**
+     * POST /requiredAndNullable
+     *
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+     * @return response (status code 200)
+     */
+    @Operation(
+        operationId = "requiredAndNullablePost",
+        tags = { "requiredAndNullable" },
+        responses = {
+            @ApiResponse(responseCode = "default", description = "response", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = RequiredAndNullable.class))
+            })
+        }
+    )
+    @RequestMapping(
+        method = RequestMethod.POST,
+        value = RequiredAndNullableApi.PATH_REQUIRED_AND_NULLABLE_POST,
+        produces = { "application/json" },
+        consumes = { "application/json" }
+    )
+    default ResponseEntity<RequiredAndNullable> requiredAndNullablePost(
+        @Parameter(name = "RequiredAndNullable", description = "bodyWithRequiredAndNullableAttributes", required = true) @Valid @RequestBody RequiredAndNullable requiredAndNullable
+    ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"str\" : \"str\", \"file\" : \"\", \"color\" : \"red\", \"onlyRequired\" : \"onlyRequired\", \"list\" : [ \"list\", \"list\" ] }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
+        return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
+
+    }
+
+}
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/FileContent.java b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/FileContent.java
new file mode 100644
index 000000000000..666e6ffdafb7
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/FileContent.java
@@ -0,0 +1,274 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonValue;
+import org.jspecify.annotations.Nullable;
+import org.openapitools.jackson.nullable.JsonNullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * FileContent
+ */
+
+@JacksonXmlRootElement(localName = "FileContent")
+@XmlRootElement(name = "FileContent")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+
+  private String name;
+
+  private Optional<Integer> size = Optional.empty();
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN("clean"),
+    
+    DETECTED("detected");
+
+    private final String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  private Optional<VirusScanEnum> virusScan = Optional.empty();
+
+  public FileContent() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters
+   */
+  public FileContent(String name) {
+    this.name = name;
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public FileContent(String name, @Nullable Integer size, @Nullable VirusScanEnum virusScan) {
+      this.name = name;
+      this.size = Optional.ofNullable(size);
+      this.virusScan = Optional.ofNullable(virusScan);
+  }
+
+  public FileContent name(String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @Schema(name = "name", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  @XmlElement(name = "name")
+  public String getName() {
+    return name;
+  }
+
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public FileContent size(@Nullable Integer size) {
+    this.size = Optional.ofNullable(size);
+    return this;
+  }
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @Schema(name = "size", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  @XmlElement(name = "size")
+  public Optional<Integer> getSize() {
+    return size;
+  }
+
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  public void setSize(Optional<Integer> size) {
+    this.size = size;
+  }
+
+  public FileContent virusScan(@Nullable VirusScanEnum virusScan) {
+    this.virusScan = Optional.ofNullable(virusScan);
+    return this;
+  }
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @Schema(name = "virusScan", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  @XmlElement(name = "virusScan")
+  public Optional<VirusScanEnum> getVirusScan() {
+    return virusScan;
+  }
+
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  public void setVirusScan(Optional<VirusScanEnum> virusScan) {
+    this.virusScan = virusScan;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(FileContent value) { 
+      this.instance.setName(value.name);
+      this.instance.setSize(value.size);
+      this.instance.setVirusScan(value.virusScan);
+      return this;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name(name);
+      return this;
+    }
+    
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size(size);
+      return this;
+    }
+    
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan(virusScan);
+      return this;
+    }
+    
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    FileContent.Builder builder = new FileContent.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/Foo.java b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/Foo.java
index 53fae78adf9f..3fb4d4b8ada4 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/Foo.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/Foo.java
@@ -131,7 +131,7 @@ public Foo nullableDt(java.time.@Nullable Instant nullableDt) {
    * @return nullableDt
    */
   @Valid 
-  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableDt")
   @JacksonXmlProperty(localName = "nullableDt")
   @XmlElement(name = "nullableDt")
@@ -177,7 +177,7 @@ public Foo nullableBinary(org.springframework.core.io.@Nullable Resource nullabl
    * @return nullableBinary
    */
   @Valid 
-  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableBinary")
   @JacksonXmlProperty(localName = "nullableBinary")
   @XmlElement(name = "nullableBinary")
@@ -263,7 +263,7 @@ public Foo nullableListMinIntems(@Nullable List<java.time.Instant> nullableListM
   }
 
   public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsItem) {
-    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent()) {
+    if (this.nullableListMinIntems == null || !this.nullableListMinIntems.isPresent() || this.nullableListMinIntems.get() == null) {
       this.nullableListMinIntems = JsonNullable.of(new ArrayList<>());
     }
     this.nullableListMinIntems.get().add(nullableListMinIntemsItem);
@@ -275,7 +275,7 @@ public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsI
    * @return nullableListMinIntems
    */
   @Valid @Size(min = 1) 
-  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableListMinIntems")
   @JacksonXmlProperty(localName = "nullableListMinIntems")
   @JacksonXmlElementWrapper(useWrapping = false)
@@ -346,7 +346,7 @@ public Foo nullableNumber(java.math.@Nullable BigDecimal nullableNumber) {
    * @return nullableNumber
    */
   @Valid 
-  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableNumber")
   @JacksonXmlProperty(localName = "nullableNumber")
   @XmlElement(name = "nullableNumber")
@@ -416,7 +416,7 @@ public Foo nullableColor(@Nullable String nullableColor) {
    * @return nullableColor
    */
   
-  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableColor")
   @JacksonXmlProperty(localName = "nullableColor")
   @XmlElement(name = "nullableColor")
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/RequiredAndNullable.java b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..3db95fb22627
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify-useOptional/src/main/java/org/openapitools/model/RequiredAndNullable.java
@@ -0,0 +1,334 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import org.openapitools.jackson.nullable.JsonNullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * RequiredAndNullable
+ */
+
+@JacksonXmlRootElement(localName = "RequiredAndNullable")
+@XmlRootElement(name = "RequiredAndNullable")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+
+  private JsonNullable<String> str = JsonNullable.<String>undefined();
+
+  private JsonNullable<org.springframework.core.io.Resource> file = JsonNullable.<org.springframework.core.io.Resource>undefined();
+
+  private JsonNullable<String> color = JsonNullable.<String>undefined();
+
+  private String onlyRequired;
+
+  private JsonNullable<List<String>> _list = JsonNullable.<List<String>>undefined();
+
+  public RequiredAndNullable() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters and all parameters
+   */
+  public RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list) {
+    this.str = JsonNullable.of(str);
+    this.file = JsonNullable.of(file);
+    this.color = JsonNullable.of(color);
+    this.onlyRequired = onlyRequired;
+    this._list = JsonNullable.of(_list);
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    this.str = JsonNullable.of(str);
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  /* @Present */ 
+  @Schema(name = "str", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  @XmlElement(name = "str")
+  public JsonNullable<String> getStr() {
+    return str;
+  }
+
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  public void setStr(JsonNullable<String> str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable file(org.springframework.core.io.@Nullable Resource file) {
+    this.file = JsonNullable.of(file);
+    return this;
+  }
+
+  /**
+   * Get file
+   * @return file
+   */
+  /* @Present */ @Valid 
+  @Schema(name = "file", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  @XmlElement(name = "file")
+  public JsonNullable<org.springframework.core.io.Resource> getFile() {
+    return file;
+  }
+
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  public void setFile(JsonNullable<org.springframework.core.io.Resource> file) {
+    this.file = file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    this.color = JsonNullable.of(color);
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  /* @Present */ 
+  @Schema(name = "color", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  @XmlElement(name = "color")
+  public JsonNullable<String> getColor() {
+    return color;
+  }
+
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  public void setColor(JsonNullable<String> color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  @NotNull 
+  @Schema(name = "onlyRequired", requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  @XmlElement(name = "onlyRequired")
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    this._list = JsonNullable.of(_list);
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null || !this._list.isPresent() || this._list.get() == null) {
+      this._list = JsonNullable.of(new ArrayList<>());
+    }
+    this._list.get().add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  /* @Present */ 
+  @Schema(name = "list", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  @XmlElement(name = "list")
+  public JsonNullable<List<String>> getList() {
+    return _list;
+  }
+
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  public void setList(JsonNullable<List<String>> _list) {
+    this._list = _list;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this.file, requiredAndNullable.file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    file: ").append(toIndentedString(file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(RequiredAndNullable value) { 
+      this.instance.setStr(value.str);
+      this.instance.setFile(value.file);
+      this.instance.setColor(value.color);
+      this.instance.setOnlyRequired(value.onlyRequired);
+      this.instance.setList(value._list);
+      return this;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str(str);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder str(JsonNullable<String> str) {
+      this.instance.str = str;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder file(org.springframework.core.io.@Nullable Resource file) {
+      this.instance.file(file);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder file(JsonNullable<org.springframework.core.io.Resource> file) {
+      this.instance.file = file;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color(color);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder color(JsonNullable<String> color) {
+      this.instance.color = color;
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired(onlyRequired);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list(_list);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder _list(JsonNullable<List<String>> _list) {
+      this.instance._list = _list;
+      return this;
+    }
+    
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    RequiredAndNullable.Builder builder = new RequiredAndNullable.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/.openapi-generator/FILES b/samples/openapi3/server/petstore/springboot-4-jspecify/.openapi-generator/FILES
index bc1941bdad50..559ef9c95db3 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify/.openapi-generator/FILES
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/.openapi-generator/FILES
@@ -3,8 +3,11 @@ pom.xml
 src/main/java/org/openapitools/api/ApiUtil.java
 src/main/java/org/openapitools/api/FileApi.java
 src/main/java/org/openapitools/api/FooApi.java
+src/main/java/org/openapitools/api/RequiredAndNullableApi.java
 src/main/java/org/openapitools/api/UploadApi.java
 src/main/java/org/openapitools/api/UploadFilesApi.java
 src/main/java/org/openapitools/api/package-info.java
+src/main/java/org/openapitools/model/FileContent.java
 src/main/java/org/openapitools/model/Foo.java
+src/main/java/org/openapitools/model/RequiredAndNullable.java
 src/main/java/org/openapitools/model/package-info.java
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/FileApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/FileApi.java
index 0ee298fc93e5..ee8c018556a2 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/FileApi.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/FileApi.java
@@ -5,6 +5,7 @@
  */
 package org.openapitools.api;
 
+import org.openapitools.model.FileContent;
 import io.swagger.v3.oas.annotations.ExternalDocumentation;
 import io.swagger.v3.oas.annotations.Operation;
 import io.swagger.v3.oas.annotations.Parameter;
@@ -52,16 +53,28 @@ default Optional<NativeWebRequest> getRequest() {
         operationId = "fileIdGet",
         tags = { "file" },
         responses = {
-            @ApiResponse(responseCode = "200", description = "ok")
+            @ApiResponse(responseCode = "200", description = "ok", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = FileContent.class))
+            })
         }
     )
     @RequestMapping(
         method = RequestMethod.GET,
-        value = FileApi.PATH_FILE_ID_GET
+        value = FileApi.PATH_FILE_ID_GET,
+        produces = { "application/json" }
     )
-    default ResponseEntity<Void> fileIdGet(
+    default ResponseEntity<FileContent> fileIdGet(
         @Parameter(name = "id", description = "", required = true, in = ParameterIn.PATH) @PathVariable("id") String id
     ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"name\" : \"name\", \"size\" : 0, \"virusScan\" : \"clean\" }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/RequiredAndNullableApi.java b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
new file mode 100644
index 000000000000..a7057ce15f82
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/api/RequiredAndNullableApi.java
@@ -0,0 +1,83 @@
+/*
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (7.25.0-SNAPSHOT).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+package org.openapitools.api;
+
+import org.openapitools.model.RequiredAndNullable;
+import io.swagger.v3.oas.annotations.ExternalDocumentation;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.Parameters;
+import io.swagger.v3.oas.annotations.media.ArraySchema;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import io.swagger.v3.oas.annotations.enums.ParameterIn;
+import io.swagger.v3.oas.annotations.media.ExampleObject;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.validation.annotation.Validated;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.multipart.MultipartFile;
+
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import jakarta.annotation.Generated;
+
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+@Validated
+@Tag(name = "requiredAndNullable", description = "requiredAndNullable")
+public interface RequiredAndNullableApi {
+
+    default Optional<NativeWebRequest> getRequest() {
+        return Optional.empty();
+    }
+
+    String PATH_REQUIRED_AND_NULLABLE_POST = "/requiredAndNullable";
+    /**
+     * POST /requiredAndNullable
+     *
+     * @param requiredAndNullable bodyWithRequiredAndNullableAttributes (required)
+     * @return response (status code 200)
+     */
+    @Operation(
+        operationId = "requiredAndNullablePost",
+        tags = { "requiredAndNullable" },
+        responses = {
+            @ApiResponse(responseCode = "default", description = "response", content = {
+                @Content(mediaType = "application/json", schema = @Schema(implementation = RequiredAndNullable.class))
+            })
+        }
+    )
+    @RequestMapping(
+        method = RequestMethod.POST,
+        value = RequiredAndNullableApi.PATH_REQUIRED_AND_NULLABLE_POST,
+        produces = { "application/json" },
+        consumes = { "application/json" }
+    )
+    default ResponseEntity<RequiredAndNullable> requiredAndNullablePost(
+        @Parameter(name = "RequiredAndNullable", description = "bodyWithRequiredAndNullableAttributes", required = true) @Valid @RequestBody RequiredAndNullable requiredAndNullable
+    ) {
+        getRequest().ifPresent(request -> {
+            for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
+                if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
+                    String exampleString = "{ \"str\" : \"str\", \"file\" : \"\", \"color\" : \"red\", \"onlyRequired\" : \"onlyRequired\", \"list\" : [ \"list\", \"list\" ] }";
+                    ApiUtil.setExampleResponse(request, "application/json", exampleString);
+                    break;
+                }
+            }
+        });
+        return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
+
+    }
+
+}
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/FileContent.java b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/FileContent.java
new file mode 100644
index 000000000000..7b0f652e20c6
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/FileContent.java
@@ -0,0 +1,281 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonSetter;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.Nulls;
+import org.jspecify.annotations.Nullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * FileContent
+ */
+
+@JacksonXmlRootElement(localName = "FileContent")
+@XmlRootElement(name = "FileContent")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class FileContent {
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  private String name;
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  @JsonSetter(nulls = Nulls.SKIP)
+  private @Nullable Integer size;
+
+  /**
+   * Gets or Sets virusScan
+   */
+  public enum VirusScanEnum {
+    CLEAN("clean"),
+    
+    DETECTED("detected");
+
+    private final String value;
+
+    VirusScanEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static VirusScanEnum fromValue(String value) {
+      for (VirusScanEnum b : VirusScanEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  @JsonSetter(nulls = Nulls.SKIP)
+  private @Nullable VirusScanEnum virusScan;
+
+  public FileContent() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters
+   */
+  public FileContent(String name) {
+    this.name = name;
+  }
+
+  /**
+   * Constructor with all args parameters
+   */
+  public FileContent(String name, @Nullable Integer size, @Nullable VirusScanEnum virusScan) {
+      this.name = name;
+      this.size = size;
+      this.virusScan = virusScan;
+  }
+
+  public FileContent name(String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name
+   */
+  
+  @Schema(name = "name", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  @XmlElement(name = "name")
+  public String getName() {
+    return name;
+  }
+
+  @JsonProperty("name")
+  @JacksonXmlProperty(localName = "name")
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public FileContent size(@Nullable Integer size) {
+    this.size = size;
+    return this;
+  }
+
+  /**
+   * Get size
+   * @return size
+   */
+  
+  @Schema(name = "size", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  @XmlElement(name = "size")
+  public @Nullable Integer getSize() {
+    return size;
+  }
+
+  @JsonProperty("size")
+  @JacksonXmlProperty(localName = "size")
+  public void setSize(@Nullable Integer size) {
+    this.size = size;
+  }
+
+  public FileContent virusScan(@Nullable VirusScanEnum virusScan) {
+    this.virusScan = virusScan;
+    return this;
+  }
+
+  /**
+   * Get virusScan
+   * @return virusScan
+   */
+  
+  @Schema(name = "virusScan", accessMode = Schema.AccessMode.READ_ONLY, requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  @XmlElement(name = "virusScan")
+  public @Nullable VirusScanEnum getVirusScan() {
+    return virusScan;
+  }
+
+  @JsonProperty("virusScan")
+  @JacksonXmlProperty(localName = "virusScan")
+  public void setVirusScan(@Nullable VirusScanEnum virusScan) {
+    this.virusScan = virusScan;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    FileContent fileContent = (FileContent) o;
+    return Objects.equals(this.name, fileContent.name) &&
+        Objects.equals(this.size, fileContent.size) &&
+        Objects.equals(this.virusScan, fileContent.virusScan);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, size, virusScan);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class FileContent {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    size: ").append(toIndentedString(size)).append("\n");
+    sb.append("    virusScan: ").append(toIndentedString(virusScan)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private FileContent instance;
+
+    public Builder() {
+      this(new FileContent());
+    }
+
+    protected Builder(FileContent instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(FileContent value) { 
+      this.instance.setName(value.name);
+      this.instance.setSize(value.size);
+      this.instance.setVirusScan(value.virusScan);
+      return this;
+    }
+
+    public FileContent.Builder name(String name) {
+      this.instance.name(name);
+      return this;
+    }
+    
+    public FileContent.Builder size(@Nullable Integer size) {
+      this.instance.size(size);
+      return this;
+    }
+    
+    public FileContent.Builder virusScan(@Nullable VirusScanEnum virusScan) {
+      this.instance.virusScan(virusScan);
+      return this;
+    }
+    
+    /**
+    * returns a built FileContent instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public FileContent build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static FileContent.Builder builder() {
+    return new FileContent.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileContent.Builder toBuilder() {
+    FileContent.Builder builder = new FileContent.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/Foo.java b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/Foo.java
index 41b025136ba6..5977f48d0055 100644
--- a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/Foo.java
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/Foo.java
@@ -145,7 +145,7 @@ public Foo nullableDt(java.time.@Nullable Instant nullableDt) {
    * @return nullableDt
    */
   @Valid 
-  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableDt", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableDt")
   @JacksonXmlProperty(localName = "nullableDt")
   @XmlElement(name = "nullableDt")
@@ -193,7 +193,7 @@ public Foo nullableBinary(org.springframework.core.io.@Nullable Resource nullabl
    * @return nullableBinary
    */
   @Valid 
-  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableBinary", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableBinary")
   @JacksonXmlProperty(localName = "nullableBinary")
   @XmlElement(name = "nullableBinary")
@@ -293,7 +293,7 @@ public Foo addNullableListMinIntemsItem(java.time.Instant nullableListMinIntemsI
    * @return nullableListMinIntems
    */
   @Valid @Size(min = 1) 
-  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableListMinIntems", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableListMinIntems")
   @JacksonXmlProperty(localName = "nullableListMinIntems")
   @JacksonXmlElementWrapper(useWrapping = false)
@@ -367,7 +367,7 @@ public Foo nullableNumber(java.math.@Nullable BigDecimal nullableNumber) {
    * @return nullableNumber
    */
   @Valid 
-  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableNumber", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableNumber")
   @JacksonXmlProperty(localName = "nullableNumber")
   @XmlElement(name = "nullableNumber")
@@ -439,7 +439,7 @@ public Foo nullableColor(@Nullable String nullableColor) {
    * @return nullableColor
    */
   
-  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableColor", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableColor")
   @JacksonXmlProperty(localName = "nullableColor")
   @XmlElement(name = "nullableColor")
diff --git a/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/RequiredAndNullable.java b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/RequiredAndNullable.java
new file mode 100644
index 000000000000..1629985f9c71
--- /dev/null
+++ b/samples/openapi3/server/petstore/springboot-4-jspecify/src/main/java/org/openapitools/model/RequiredAndNullable.java
@@ -0,0 +1,319 @@
+package org.openapitools.model;
+
+import java.net.URI;
+import java.util.Objects;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import org.jspecify.annotations.Nullable;
+import java.time.OffsetDateTime;
+import jakarta.validation.Valid;
+import jakarta.validation.constraints.*;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+import tools.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import jakarta.xml.bind.annotation.*;
+
+import java.util.*;
+import jakarta.annotation.Generated;
+
+/**
+ * RequiredAndNullable
+ */
+
+@JacksonXmlRootElement(localName = "RequiredAndNullable")
+@XmlRootElement(name = "RequiredAndNullable")
+@XmlAccessorType(XmlAccessType.FIELD)
+@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.25.0-SNAPSHOT")
+public class RequiredAndNullable {
+
+  @JsonInclude(JsonInclude.Include.ALWAYS)
+  private @Nullable String str = null;
+
+  @JsonInclude(JsonInclude.Include.ALWAYS)
+  private org.springframework.core.io.@Nullable Resource file = null;
+
+  @JsonInclude(JsonInclude.Include.ALWAYS)
+  private @Nullable String color = null;
+
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  private String onlyRequired;
+
+  @JsonInclude(JsonInclude.Include.ALWAYS)
+  private @Nullable List<String> _list;
+
+  public RequiredAndNullable() {
+    super();
+  }
+
+  /**
+   * Constructor with only required parameters and all parameters
+   */
+  public RequiredAndNullable(@Nullable String str, org.springframework.core.io.@Nullable Resource file, @Nullable String color, String onlyRequired, @Nullable List<String> _list) {
+    this.str = str;
+    this.file = file;
+    this.color = color;
+    this.onlyRequired = onlyRequired;
+    this._list = _list;
+  }
+
+  public RequiredAndNullable str(@Nullable String str) {
+    this.str = str;
+    return this;
+  }
+
+  /**
+   * Get str
+   * @return str
+   */
+  
+  @Schema(name = "str", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  @XmlElement(name = "str")
+  public @Nullable String getStr() {
+    return str;
+  }
+
+  @JsonProperty("str")
+  @JacksonXmlProperty(localName = "str")
+  public void setStr(@Nullable String str) {
+    this.str = str;
+  }
+
+  public RequiredAndNullable file(org.springframework.core.io.@Nullable Resource file) {
+    this.file = file;
+    return this;
+  }
+
+  /**
+   * Get file
+   * @return file
+   */
+  @Valid 
+  @Schema(name = "file", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  @XmlElement(name = "file")
+  public org.springframework.core.io.@Nullable Resource getFile() {
+    return file;
+  }
+
+  @JsonProperty("file")
+  @JacksonXmlProperty(localName = "file")
+  public void setFile(org.springframework.core.io.@Nullable Resource file) {
+    this.file = file;
+  }
+
+  public RequiredAndNullable color(@Nullable String color) {
+    this.color = color;
+    return this;
+  }
+
+  /**
+   * Get color
+   * @return color
+   */
+  
+  @Schema(name = "color", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  @XmlElement(name = "color")
+  public @Nullable String getColor() {
+    return color;
+  }
+
+  @JsonProperty("color")
+  @JacksonXmlProperty(localName = "color")
+  public void setColor(@Nullable String color) {
+    this.color = color;
+  }
+
+  public RequiredAndNullable onlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+    return this;
+  }
+
+  /**
+   * Get onlyRequired
+   * @return onlyRequired
+   */
+  @NotNull 
+  @Schema(name = "onlyRequired", requiredMode = Schema.RequiredMode.REQUIRED)
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  @XmlElement(name = "onlyRequired")
+  public String getOnlyRequired() {
+    return onlyRequired;
+  }
+
+  @JsonProperty("onlyRequired")
+  @JacksonXmlProperty(localName = "onlyRequired")
+  public void setOnlyRequired(String onlyRequired) {
+    this.onlyRequired = onlyRequired;
+  }
+
+  public RequiredAndNullable _list(@Nullable List<String> _list) {
+    this._list = _list;
+    return this;
+  }
+
+  public RequiredAndNullable addListItem(String _listItem) {
+    if (this._list == null) {
+      this._list = new ArrayList<>();
+    }
+    this._list.add(_listItem);
+    return this;
+  }
+
+  /**
+   * Get _list
+   * @return _list
+   */
+  
+  @Schema(name = "list", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  @XmlElement(name = "list")
+  public @Nullable List<String> getList() {
+    return _list;
+  }
+
+  @JsonProperty("list")
+  @JacksonXmlProperty(localName = "list")
+  @JacksonXmlElementWrapper(useWrapping = false)
+  public void setList(@Nullable List<String> _list) {
+    this._list = _list;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    RequiredAndNullable requiredAndNullable = (RequiredAndNullable) o;
+    return Objects.equals(this.str, requiredAndNullable.str) &&
+        Objects.equals(this.file, requiredAndNullable.file) &&
+        Objects.equals(this.color, requiredAndNullable.color) &&
+        Objects.equals(this.onlyRequired, requiredAndNullable.onlyRequired) &&
+        Objects.equals(this._list, requiredAndNullable._list);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(str, file, color, onlyRequired, _list);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class RequiredAndNullable {\n");
+    sb.append("    str: ").append(toIndentedString(str)).append("\n");
+    sb.append("    file: ").append(toIndentedString(file)).append("\n");
+    sb.append("    color: ").append(toIndentedString(color)).append("\n");
+    sb.append("    onlyRequired: ").append(toIndentedString(onlyRequired)).append("\n");
+    sb.append("    _list: ").append(toIndentedString(_list)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(@Nullable Object o) {
+    return o == null ? "null" : o.toString().replace("\n", "\n    ");
+  }
+  
+  public static class Builder {
+
+    private RequiredAndNullable instance;
+
+    public Builder() {
+      this(new RequiredAndNullable());
+    }
+
+    protected Builder(RequiredAndNullable instance) {
+      this.instance = instance;
+    }
+
+    protected Builder copyOf(RequiredAndNullable value) { 
+      this.instance.setStr(value.str);
+      this.instance.setFile(value.file);
+      this.instance.setColor(value.color);
+      this.instance.setOnlyRequired(value.onlyRequired);
+      this.instance.setList(value._list);
+      return this;
+    }
+
+    public RequiredAndNullable.Builder str(@Nullable String str) {
+      this.instance.str(str);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder file(org.springframework.core.io.@Nullable Resource file) {
+      this.instance.file(file);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder color(@Nullable String color) {
+      this.instance.color(color);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder onlyRequired(String onlyRequired) {
+      this.instance.onlyRequired(onlyRequired);
+      return this;
+    }
+    
+    public RequiredAndNullable.Builder _list(@Nullable List<String> _list) {
+      this.instance._list(_list);
+      return this;
+    }
+    
+    /**
+    * returns a built RequiredAndNullable instance.
+    *
+    * The builder is not reusable (NullPointerException)
+    */
+    public RequiredAndNullable build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field (except for the default values).
+  */
+  public static RequiredAndNullable.Builder builder() {
+    return new RequiredAndNullable.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public RequiredAndNullable.Builder toBuilder() {
+    RequiredAndNullable.Builder builder = new RequiredAndNullable.Builder();
+    return builder.copyOf(this);
+  }
+
+}
+
diff --git a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/openapi3/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/openapi3/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/spring-boot-defaultInterface-unhandledExcp/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/spring-boot-nullable-set/src/main/java/org/openapitools/model/ObjectWithUniqueItems.java b/samples/server/petstore/spring-boot-nullable-set/src/main/java/org/openapitools/model/ObjectWithUniqueItems.java
index 430f680158d4..30bff5f61534 100644
--- a/samples/server/petstore/spring-boot-nullable-set/src/main/java/org/openapitools/model/ObjectWithUniqueItems.java
+++ b/samples/server/petstore/spring-boot-nullable-set/src/main/java/org/openapitools/model/ObjectWithUniqueItems.java
@@ -57,7 +57,7 @@ public ObjectWithUniqueItems nullSet(Set<String> nullSet) {
   }
 
   public ObjectWithUniqueItems addNullSetItem(String nullSetItem) {
-    if (this.nullSet == null || !this.nullSet.isPresent()) {
+    if (this.nullSet == null || !this.nullSet.isPresent() || this.nullSet.get() == null) {
       this.nullSet = JsonNullable.of(new LinkedHashSet<>());
     }
     this.nullSet.get().add(nullSetItem);
@@ -69,7 +69,7 @@ public ObjectWithUniqueItems addNullSetItem(String nullSetItem) {
    * @return nullSet
    */
   
-  @Schema(name = "nullSet", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullSet", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullSet")
   public JsonNullable<Set<String>> getNullSet() {
     return nullSet;
@@ -115,7 +115,7 @@ public ObjectWithUniqueItems nullList(List<String> nullList) {
   }
 
   public ObjectWithUniqueItems addNullListItem(String nullListItem) {
-    if (this.nullList == null || !this.nullList.isPresent()) {
+    if (this.nullList == null || !this.nullList.isPresent() || this.nullList.get() == null) {
       this.nullList = JsonNullable.of(new ArrayList<>());
     }
     this.nullList.get().add(nullListItem);
@@ -127,7 +127,7 @@ public ObjectWithUniqueItems addNullListItem(String nullListItem) {
    * @return nullList
    */
   
-  @Schema(name = "nullList", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullList", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullList")
   public JsonNullable<List<String>> getNullList() {
     return nullList;
diff --git a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index 8c8fef587001..047b517697a9 100644
--- a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -333,7 +333,7 @@ public AdditionalPropertiesClass anytype2(@Nullable Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public @Nullable Object getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 6674c88a2e4f..d662c38a4a75 100644
--- a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -65,7 +65,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public @Nullable List<String> getNullableArray() {
     return nullableArray;
@@ -93,8 +93,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public List<String> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -152,7 +152,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public @Nullable List<String> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/NullableMapProperty.java
index 855c53622446..0c9a62ab9578 100644
--- a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -43,7 +43,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public @Nullable Map<String, String> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ParentWithNullable.java
index 032a06cb2a2b..069e175455ce 100644
--- a/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-beanvalidation-no-nullable/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -107,7 +107,7 @@ public ParentWithNullable nullableProperty(@Nullable String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public @Nullable String getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-builtin-validation/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index 32023ee3da1e..8f54cd848b67 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -346,7 +346,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index b6557ceff4e9..ce39cfc4f753 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -66,7 +66,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -78,7 +78,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -94,7 +94,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -105,8 +105,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -152,7 +152,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -164,7 +164,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
index e2ceeea637fe..3db7f9296c5b 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -46,7 +46,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -58,7 +58,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
index 50c34a0c9121..dfa072f98090 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -120,7 +120,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index 3f6cf5af234f..d8c6725ed27c 100644
--- a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 1e996c854efe..b7d3d6d42d75 100644
--- a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
index 56d45c3ad292..71380912bcc1 100644
--- a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
index af16949486cc..75408c9a5421 100644
--- a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
index 9ea7f74985a9..4b738ea3239f 100644
--- a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
+++ b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
@@ -327,7 +327,7 @@ public AdditionalPropertiesClassDto anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index 2bc02f7a7cc3..6c8f9274fcdf 100644
--- a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -58,7 +58,7 @@ public ContainerDefaultValueDto nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -70,7 +70,7 @@ public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -86,7 +86,7 @@ public ContainerDefaultValueDto nullableRequiredArray(List<String> nullableRequi
   }
 
   public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -97,8 +97,8 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -144,7 +144,7 @@ public ContainerDefaultValueDto nullableArrayWithDefault(List<String> nullableAr
   }
 
   public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -156,7 +156,7 @@ public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableA
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/NullableMapPropertyDto.java b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
index 98ba228cdc9b..6f63407a6d66 100644
--- a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
+++ b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
@@ -37,7 +37,7 @@ public NullableMapPropertyDto languageValues(Map<String, String> languageValues)
   }
 
   public NullableMapPropertyDto putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -49,7 +49,7 @@ public NullableMapPropertyDto putLanguageValuesItem(String key, String languageV
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ParentWithNullableDto.java b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ParentWithNullableDto.java
index 982f8d038258..213234e9599f 100644
--- a/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ParentWithNullableDto.java
+++ b/samples/server/petstore/springboot-include-http-request-context/src/main/java/org/openapitools/model/ParentWithNullableDto.java
@@ -109,7 +109,7 @@ public ParentWithNullableDto nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-reactive-noResponseEntity/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index fc4f770ac1d9..4105491f50a1 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index a51bd99c90fc..2828ceb3a770 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
index 31127013b739..1e54ce87a90f 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ParentWithNullable.java
index d394b3e38431..dd5243a5203a 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/NullableModel.java b/samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/NullableModel.java
index e6fa1ccea8b4..dfaee4afe5db 100644
--- a/samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/NullableModel.java
+++ b/samples/server/petstore/springboot-sort-validation/src/main/java/org/openapitools/model/NullableModel.java
@@ -80,7 +80,7 @@ public NullableModel requiredNullable(String requiredNullable) {
    * Get requiredNullable
    * @return requiredNullable
    */
-  @NotNull 
+  /* @Present */ 
   @JsonProperty("requiredNullable")
   public JsonNullable<String> getRequiredNullable() {
     return requiredNullable;
diff --git a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
index f28336e48905..0bc3c35c6272 100644
--- a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ContainerDefaultValue.java
index 89a4873f502e..a023236fb245 100644
--- a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/NullableMapProperty.java b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/NullableMapProperty.java
index 1c8b66beb4e6..199467adfb4a 100644
--- a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ParentWithNullable.java b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ParentWithNullable.java
index db85e72833c9..2258fe6d6c95 100644
--- a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/AdditionalPropertiesClass.java b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/AdditionalPropertiesClass.java
index 51f8239e6287..283ef0c9edf8 100644
--- a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/AdditionalPropertiesClass.java
+++ b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/AdditionalPropertiesClass.java
@@ -325,7 +325,7 @@ public AdditionalPropertiesClass anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ContainerDefaultValue.java b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ContainerDefaultValue.java
index 2bd4f51c4140..6c4935f5803c 100644
--- a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ContainerDefaultValue.java
+++ b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ContainerDefaultValue.java
@@ -56,7 +56,7 @@ public ContainerDefaultValue nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -68,7 +68,7 @@ public ContainerDefaultValue addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -84,7 +84,7 @@ public ContainerDefaultValue nullableRequiredArray(List<String> nullableRequired
   }
 
   public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -95,8 +95,8 @@ public ContainerDefaultValue addNullableRequiredArrayItem(String nullableRequire
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -142,7 +142,7 @@ public ContainerDefaultValue nullableArrayWithDefault(List<String> nullableArray
   }
 
   public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -154,7 +154,7 @@ public ContainerDefaultValue addNullableArrayWithDefaultItem(String nullableArra
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/NullableMapProperty.java b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/NullableMapProperty.java
index fc013fe70f4c..64a065bae769 100644
--- a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/NullableMapProperty.java
+++ b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/NullableMapProperty.java
@@ -35,7 +35,7 @@ public NullableMapProperty languageValues(Map<String, String> languageValues) {
   }
 
   public NullableMapProperty putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -47,7 +47,7 @@ public NullableMapProperty putLanguageValuesItem(String key, String languageValu
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ParentWithNullable.java b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ParentWithNullable.java
index bb28729decdd..c8ccf5a155c1 100644
--- a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ParentWithNullable.java
+++ b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/model/ParentWithNullable.java
@@ -108,7 +108,7 @@ public ParentWithNullable nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/EnumTestDto.java b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/EnumTestDto.java
index 1576c5046e33..4b646de3b597 100644
--- a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/EnumTestDto.java
+++ b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/EnumTestDto.java
@@ -305,7 +305,7 @@ public EnumTestDto outerEnum(OuterEnumDto outerEnum) {
    * @return outerEnum
    */
   @Valid 
-  @Schema(name = "outerEnum", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "outerEnum", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("outerEnum")
   public JsonNullable<OuterEnumDto> getOuterEnum() {
     return outerEnum;
diff --git a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/HealthCheckResultDto.java b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/HealthCheckResultDto.java
index ac09a0a9834b..edb49de12b67 100644
--- a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/HealthCheckResultDto.java
+++ b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/HealthCheckResultDto.java
@@ -40,7 +40,7 @@ public HealthCheckResultDto nullableMessage(String nullableMessage) {
    * @return nullableMessage
    */
   
-  @Schema(name = "NullableMessage", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "NullableMessage", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("NullableMessage")
   public JsonNullable<String> getNullableMessage() {
     return nullableMessage;
diff --git a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/NullableClassDto.java b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/NullableClassDto.java
index 55fe5702be7f..8631a088be7f 100644
--- a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/NullableClassDto.java
+++ b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/NullableClassDto.java
@@ -78,7 +78,7 @@ public NullableClassDto integerProp(Integer integerProp) {
    * @return integerProp
    */
   
-  @Schema(name = "integer_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "integer_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("integer_prop")
   public JsonNullable<Integer> getIntegerProp() {
     return integerProp;
@@ -98,7 +98,7 @@ public NullableClassDto numberProp(BigDecimal numberProp) {
    * @return numberProp
    */
   @Valid 
-  @Schema(name = "number_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "number_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("number_prop")
   public JsonNullable<BigDecimal> getNumberProp() {
     return numberProp;
@@ -118,7 +118,7 @@ public NullableClassDto booleanProp(Boolean booleanProp) {
    * @return booleanProp
    */
   
-  @Schema(name = "boolean_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "boolean_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("boolean_prop")
   public JsonNullable<Boolean> getBooleanProp() {
     return booleanProp;
@@ -138,7 +138,7 @@ public NullableClassDto stringProp(String stringProp) {
    * @return stringProp
    */
   
-  @Schema(name = "string_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "string_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("string_prop")
   public JsonNullable<String> getStringProp() {
     return stringProp;
@@ -158,7 +158,7 @@ public NullableClassDto dateProp(LocalDate dateProp) {
    * @return dateProp
    */
   @Valid 
-  @Schema(name = "date_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "date_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("date_prop")
   public JsonNullable<LocalDate> getDateProp() {
     return dateProp;
@@ -178,7 +178,7 @@ public NullableClassDto datetimeProp(OffsetDateTime datetimeProp) {
    * @return datetimeProp
    */
   @Valid 
-  @Schema(name = "datetime_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "datetime_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("datetime_prop")
   public JsonNullable<OffsetDateTime> getDatetimeProp() {
     return datetimeProp;
@@ -194,7 +194,7 @@ public NullableClassDto arrayNullableProp(List<Object> arrayNullableProp) {
   }
 
   public NullableClassDto addArrayNullablePropItem(Object arrayNullablePropItem) {
-    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
+    if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent() || this.arrayNullableProp.get() == null) {
       this.arrayNullableProp = JsonNullable.of(new ArrayList<>());
     }
     this.arrayNullableProp.get().add(arrayNullablePropItem);
@@ -206,7 +206,7 @@ public NullableClassDto addArrayNullablePropItem(Object arrayNullablePropItem) {
    * @return arrayNullableProp
    */
   
-  @Schema(name = "array_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "array_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("array_nullable_prop")
   public JsonNullable<List<Object>> getArrayNullableProp() {
     return arrayNullableProp;
@@ -222,7 +222,7 @@ public NullableClassDto arrayAndItemsNullableProp(List<Object> arrayAndItemsNull
   }
 
   public NullableClassDto addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
-    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
+    if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent() || this.arrayAndItemsNullableProp.get() == null) {
       this.arrayAndItemsNullableProp = JsonNullable.of(new ArrayList<>());
     }
     this.arrayAndItemsNullableProp.get().add(arrayAndItemsNullablePropItem);
@@ -234,7 +234,7 @@ public NullableClassDto addArrayAndItemsNullablePropItem(Object arrayAndItemsNul
    * @return arrayAndItemsNullableProp
    */
   
-  @Schema(name = "array_and_items_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "array_and_items_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("array_and_items_nullable_prop")
   public JsonNullable<List<Object>> getArrayAndItemsNullableProp() {
     return arrayAndItemsNullableProp;
@@ -279,7 +279,7 @@ public NullableClassDto objectNullableProp(Map<String, Object> objectNullablePro
   }
 
   public NullableClassDto putObjectNullablePropItem(String key, Object objectNullablePropItem) {
-    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
+    if (this.objectNullableProp == null || !this.objectNullableProp.isPresent() || this.objectNullableProp.get() == null) {
       this.objectNullableProp = JsonNullable.of(new HashMap<>());
     }
     this.objectNullableProp.get().put(key, objectNullablePropItem);
@@ -291,7 +291,7 @@ public NullableClassDto putObjectNullablePropItem(String key, Object objectNulla
    * @return objectNullableProp
    */
   
-  @Schema(name = "object_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "object_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("object_nullable_prop")
   public JsonNullable<Map<String, Object>> getObjectNullableProp() {
     return objectNullableProp;
@@ -307,7 +307,7 @@ public NullableClassDto objectAndItemsNullableProp(Map<String, Object> objectAnd
   }
 
   public NullableClassDto putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
-    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
+    if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent() || this.objectAndItemsNullableProp.get() == null) {
       this.objectAndItemsNullableProp = JsonNullable.of(new HashMap<>());
     }
     this.objectAndItemsNullableProp.get().put(key, objectAndItemsNullablePropItem);
@@ -319,7 +319,7 @@ public NullableClassDto putObjectAndItemsNullablePropItem(String key, Object obj
    * @return objectAndItemsNullableProp
    */
   
-  @Schema(name = "object_and_items_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "object_and_items_nullable_prop", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("object_and_items_nullable_prop")
   public JsonNullable<Map<String, Object>> getObjectAndItemsNullableProp() {
     return objectAndItemsNullableProp;
diff --git a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/ParentWithNullableDto.java b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/ParentWithNullableDto.java
index 982f8d038258..213234e9599f 100644
--- a/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/ParentWithNullableDto.java
+++ b/samples/server/petstore/springboot-x-implements-skip/src/main/java/org/openapitools/model/ParentWithNullableDto.java
@@ -109,7 +109,7 @@ public ParentWithNullableDto nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;
diff --git a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
index 3115be7ad0b3..54a246e65c81 100644
--- a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
+++ b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/AdditionalPropertiesClassDto.java
@@ -327,7 +327,7 @@ public AdditionalPropertiesClassDto anytype2(Object anytype2) {
    * @return anytype2
    */
   
-  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "anytype_2", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("anytype_2")
   public JsonNullable<Object> getAnytype2() {
     return anytype2;
diff --git a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
index 39f4e40b9ba0..ba50a4de0576 100644
--- a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
+++ b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ContainerDefaultValueDto.java
@@ -58,7 +58,7 @@ public ContainerDefaultValueDto nullableArray(List<String> nullableArray) {
   }
 
   public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
-    if (this.nullableArray == null || !this.nullableArray.isPresent()) {
+    if (this.nullableArray == null || !this.nullableArray.isPresent() || this.nullableArray.get() == null) {
       this.nullableArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableArray.get().add(nullableArrayItem);
@@ -70,7 +70,7 @@ public ContainerDefaultValueDto addNullableArrayItem(String nullableArrayItem) {
    * @return nullableArray
    */
   
-  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array")
   public JsonNullable<List<String>> getNullableArray() {
     return nullableArray;
@@ -86,7 +86,7 @@ public ContainerDefaultValueDto nullableRequiredArray(List<String> nullableRequi
   }
 
   public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequiredArrayItem) {
-    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent()) {
+    if (this.nullableRequiredArray == null || !this.nullableRequiredArray.isPresent() || this.nullableRequiredArray.get() == null) {
       this.nullableRequiredArray = JsonNullable.of(new ArrayList<>());
     }
     this.nullableRequiredArray.get().add(nullableRequiredArrayItem);
@@ -97,8 +97,8 @@ public ContainerDefaultValueDto addNullableRequiredArrayItem(String nullableRequ
    * Get nullableRequiredArray
    * @return nullableRequiredArray
    */
-  @NotNull 
-  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED)
+  /* @Present */ 
+  @Schema(name = "nullable_required_array", requiredMode = Schema.RequiredMode.REQUIRED, nullable = true)
   @JsonProperty("nullable_required_array")
   public JsonNullable<List<String>> getNullableRequiredArray() {
     return nullableRequiredArray;
@@ -144,7 +144,7 @@ public ContainerDefaultValueDto nullableArrayWithDefault(List<String> nullableAr
   }
 
   public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableArrayWithDefaultItem) {
-    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent()) {
+    if (this.nullableArrayWithDefault == null || !this.nullableArrayWithDefault.isPresent() || this.nullableArrayWithDefault.get() == null) {
       this.nullableArrayWithDefault = JsonNullable.of(new ArrayList<>(Arrays.asList("foo", "bar")));
     }
     this.nullableArrayWithDefault.get().add(nullableArrayWithDefaultItem);
@@ -156,7 +156,7 @@ public ContainerDefaultValueDto addNullableArrayWithDefaultItem(String nullableA
    * @return nullableArrayWithDefault
    */
   
-  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullable_array_with_default", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullable_array_with_default")
   public JsonNullable<List<String>> getNullableArrayWithDefault() {
     return nullableArrayWithDefault;
diff --git a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/NullableMapPropertyDto.java b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
index 50958c247610..0e002790e407 100644
--- a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
+++ b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/NullableMapPropertyDto.java
@@ -37,7 +37,7 @@ public NullableMapPropertyDto languageValues(Map<String, String> languageValues)
   }
 
   public NullableMapPropertyDto putLanguageValuesItem(String key, String languageValuesItem) {
-    if (this.languageValues == null || !this.languageValues.isPresent()) {
+    if (this.languageValues == null || !this.languageValues.isPresent() || this.languageValues.get() == null) {
       this.languageValues = JsonNullable.of(new HashMap<>());
     }
     this.languageValues.get().put(key, languageValuesItem);
@@ -49,7 +49,7 @@ public NullableMapPropertyDto putLanguageValuesItem(String key, String languageV
    * @return languageValues
    */
   
-  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "languageValues", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("languageValues")
   public JsonNullable<Map<String, String>> getLanguageValues() {
     return languageValues;
diff --git a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ParentWithNullableDto.java b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ParentWithNullableDto.java
index af2b3803d750..590d7f63bc93 100644
--- a/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ParentWithNullableDto.java
+++ b/samples/server/petstore/springboot/src/main/java/org/openapitools/model/ParentWithNullableDto.java
@@ -110,7 +110,7 @@ public ParentWithNullableDto nullableProperty(String nullableProperty) {
    * @return nullableProperty
    */
   
-  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED)
+  @Schema(name = "nullableProperty", requiredMode = Schema.RequiredMode.NOT_REQUIRED, nullable = true)
   @JsonProperty("nullableProperty")
   public JsonNullable<String> getNullableProperty() {
     return nullableProperty;