Fixed double iter.next()

api/src/main/java/javax/jdo/spi/JDOImplHelper.java

@@ -584,17 +584,19 @@ public static void registerAuthorizedStateManagerClasses(Collection<?> smClasses
     SecurityManager sm = LegacyJava.getSecurityManager();
     if (sm != null) {
       sm.checkPermission(JDOPermission.SET_STATE_MANAGER);
-      synchronized (authorizedStateManagerClasses) {
-        for (Iterator<?> it = smClasses.iterator(); it.hasNext(); ) {
-          Object smClass = it.next();
-          if (!(smClass instanceof Class)) {
-            throw new ClassCastException(
-                msg.msg(
-                    "ERR_StateManagerClassCast", // NOI18N
-                    smClass.getClass().getName()));
-          }
-          registerAuthorizedStateManagerClass((Class<?>) it.next());
+    }
+    synchronized (authorizedStateManagerClasses) {
+      for (Object smClass : smClasses) {
+        if (!(smClass instanceof Class)) {
+          throw new ClassCastException(
+              msg.msg(
+                  "ERR_StateManagerClassCast", // NOI18N
+                  smClass.getClass().getName()));
         }
+        // register the element that was just validated (the loop formerly advanced the
+        // iterator a second time here, registering the unvalidated successor instead and
+        // throwing NoSuchElementException on odd-sized collections)
+        registerAuthorizedStateManagerClass((Class<?>) smClass);
       }
     }
   }

api/src/test/java/javax/jdo/spi/JDOImplHelperTest.java

@@ -17,7 +17,9 @@
 
 package javax.jdo.spi;
 
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.List;
 import java.util.Properties;
 import javax.jdo.Constants;
 import javax.jdo.JDOUserException;
@@ -168,6 +170,29 @@ void testClassListenerRegistration() {
     Assertions.assertNull(event, "Unexpected event ");
   }
 
+  /**
+   * Test that registerAuthorizedStateManagerClasses validates and registers every element of the
+   * collection. The loop formerly advanced the iterator twice per iteration, registering the
+   * unvalidated successor of each validated element and throwing NoSuchElementException on
+   * odd-sized collections.
+   */
+  @Test
+  void testRegisterAuthorizedStateManagerClassesOddSized() {
+    List<Class<?>> classes = Arrays.asList(String.class, Integer.class, Long.class);
+    // must validate and register all three elements without NoSuchElementException
+    JDOImplHelper.registerAuthorizedStateManagerClasses(classes);
+  }
+
+  /** Test that a non-Class element is rejected with the documented ClassCastException. */
+  @Test
+  void testRegisterAuthorizedStateManagerClassesNonClassElement() {
+    List<Object> elements = Arrays.asList(String.class, "not a class");
+    Assertions.assertThrows(
+        ClassCastException.class,
+        () -> JDOImplHelper.registerAuthorizedStateManagerClasses(elements),
+        "Missing ClassCastException for non-Class element");
+  }
+
   /** Test that an unknown standard property causes JDOUserException. */
   @Test
   void testUnknownStandardProperty() {