Database migrations are the most dangerous code in most applications. A failed migration in production means downtime. A migration that succeeds but corrupts data is worse. Testing migrations against the actual target database — not H2, not a manual inspection — is the only way to catch migration bugs before they reach production. This article covers testing Flyway and Liquibase migrations with Testcontainers, verifying schema correctness after migration, and testing rollback scenarios.

Testing database code against H2 gives you a false sense of security. PostgreSQL has different behavior for ON CONFLICT, RETURNING, JSON operators, full-text search, and dozens of other features. A JPA query that works in H2 dialect may fail against real PostgreSQL. This article shows how to test your Spring Data JPA repositories, custom queries, and database constraints against a real PostgreSQL instance using Testcontainers. What You’ll Learn @ServiceConnection — the Spring Boot 3.

PostgreSQL offers powerful features beyond basic SQL — JSONB, arrays, full-text search, advisory locks. This article shows how to use them from Spring Boot and how to tune HikariCP for production. Project Setup <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.postgresql</groupId> <artifactId>postgresql</artifactId> <scope>runtime</scope> </dependency> spring: datasource: url: jdbc:postgresql://localhost:5432/orderdb username: app password: ${DB_PASSWORD} driver-class-name: org.postgresql.Driver jpa: database-platform: org.hibernate.dialect.PostgreSQLDialect hibernate: ddl-auto: validate HikariCP — Connection Pool Tuning Spring Boot uses HikariCP by default — the fastest JDBC connection pool.