Merchant API

Merchant API is a Spring Boot REST service for managing merchants and their payment transactions. The project is being modernized as a clean, production-minded Java backend portfolio application with simple architecture, explicit configuration, and database migrations.

Current Stack

• Java 21
• Spring Boot 3.5
• Spring Web
• Spring Data JPA / Hibernate
• Oracle JDBC for local and production-style runtime
• Flyway for SQL database migrations
• H2 for test execution
• Maven Wrapper

API Surface

POST /api/v1/merchants
GET  /api/v1/merchants/{merchantId}

POST /api/v1/transactions
GET  /api/v1/transactions
GET  /api/v1/merchants/{merchantId}/transactions

Configuration

Runtime database settings are externalized through environment variables. Local defaults are provided for convenience.

SPRING_DATASOURCE_URL
SPRING_DATASOURCE_USERNAME
SPRING_DATASOURCE_PASSWORD

Default local values:

jdbc:oracle:thin:@localhost:1521:orcl
system
oracle

The application uses Flyway migrations from profile-specific folders:

src/main/resources/db/migration/oracle
src/main/resources/db/migration/h2

JPA schema generation is disabled for safety. Hibernate validates the schema created by Flyway.

Profiles

The default profile targets Oracle using externalized datasource settings.

The test profile uses an in-memory H2 database in Oracle compatibility mode so tests can run without a local Oracle instance.

Build And Test

.\mvnw.cmd clean compile
.\mvnw.cmd clean test

Local Run

Set database credentials if your Oracle setup differs from the defaults:

$env:SPRING_DATASOURCE_URL="jdbc:oracle:thin:@localhost:1521:orcl"
$env:SPRING_DATASOURCE_USERNAME="system"
$env:SPRING_DATASOURCE_PASSWORD="oracle"
.\mvnw.cmd spring-boot:run