Java Spring Development Best Practices Core Principles Write clean, efficient, and well-documented Java code with accurate Spring Boot examples Use Spring Boot 3.x with Java 17+ features (records, sealed classes, pattern matching) Prefer constructor injection over field injection for better testability Follow SOLID principles and RESTful API design patterns Design for microservices architecture suitability Project Structure
Organize code using the standard layered pattern:
project/ ├── controllers/ # REST controllers ├── services/ # Business logic ├── repositories/ # Data access layer ├── models/ # Domain entities and DTOs └── configurations/ # Spring configurations
Dependency Injection Use constructor injection for required dependencies Leverage @RequiredArgsConstructor with Lombok for cleaner code Keep constructors simple and avoid logic in them Use @Qualifier when multiple implementations exist REST API Design Use appropriate HTTP methods (GET, POST, PUT, DELETE, PATCH) Return proper HTTP status codes Implement consistent error response format Use DTOs to control API contract Version APIs when needed Data Access Spring Data JPA Define proper entity relationships (@OneToMany, @ManyToOne, etc.) Use lazy loading appropriately to avoid N+1 queries Implement pagination for large result sets Use query methods and @Query for custom queries Database Migrations Use Flyway or Liquibase for schema migrations Version migration scripts properly Never modify existing migrations Test migrations in development before production Security Spring Security Implement authentication and authorization properly Use BCrypt for password encoding Configure CORS appropriately Protect endpoints based on roles/permissions Use HTTPS in production Secure Coding Validate all user inputs Sanitize data to prevent injection attacks Avoid exposing sensitive information in responses Use parameterized queries Testing Unit Testing Use JUnit 5 for unit tests Mock dependencies with Mockito Test business logic thoroughly Follow Given-When-Then pattern Integration Testing Use @SpringBootTest for integration tests Use MockMvc for web layer testing Test database operations with test containers Test security configurations Performance Caching Use Spring Cache abstraction Configure appropriate cache providers (Redis, Caffeine) Set proper TTL for cached data Implement cache eviction strategies Async Processing Use @Async for non-blocking operations Configure thread pools appropriately Handle exceptions in async methods Consider using reactive patterns for high concurrency Logging and Monitoring Logging Use SLF4J with Logback Log at appropriate levels Include correlation IDs for tracing Avoid logging sensitive data Monitoring Use Spring Boot Actuator for health and metrics Export metrics to monitoring systems Set up proper health checks Monitor application performance API Documentation Use Springdoc OpenAPI for API documentation Document all endpoints with descriptions Include request/response examples Keep documentation up to date with code