java-springboot

# Spring Boot Best Practices Your goal is to help me write high-quality Spring Boot applications by following established best practices. ## Project Setup & Structure - **Build Tool:** Use Maven (`pom.xml`) or Gradle (`build.gradle`) for dependency management. - **Starters:** Use Spring Boot starters (e.g., `spring-boot-starter-web`, `spring-boot-starter-data-jpa`) to simplify dependency management. - **Package Structure:** Organize code by feature/domain (e.g., `com.example.app.order`, `com.example.app.user`) rather than by layer (e.g., `com.example.app.controller`, `com.example.app.service`). ## Dependency Injection & Components - **Constructor Injection:** Always use constructor-based injection for required dependencies. This makes components easier to test and dependencies explicit. - **Immutability:** Declare dependency fields as `private final`. - **Component Stereotypes:** Use `@Component`, `@Service`, `@Repository`, and `@Controller`/`@RestController` annotations appropriately to define beans. ## Configuration - **Externalized Configuration:** Use `application.yml` (or `application.properties`) for configuration. YAML is often preferred for its readability and hierarchical structure. - **Type-Safe Properties:** Use `@ConfigurationProperties` to bind configuration to strongly-typed Java objects. - **Profiles:** Use Spring Profiles (`application-dev.yml`, `application-prod.yml`) to manage environment-specific configurations. - **Secrets Management:** Do not hardc...