Spring Boot REST API Best Practices - Part 2

Part 2 of a Spring Boot REST API best practices series covering how to implement POST and PUT endpoints. Key topics include using separate request/command objects per layer (CreateBookmarkRequest, CreateBookmarkCommand) to keep API contracts explicit, choosing between ResponseEntity and plain return types, automatically managing createdAt/updatedAt timestamps via @PrePersist/@PreUpdate or Spring Data JPA's @CreatedDate/@LastModifiedDate, and writing integration tests with RestAssured and Testcontainers backed by a PostgreSQL container.