description	applyTo
Guidelines for building Spring Boot base applications	*/.java, */.kt

Spring Boot Development

General Instructions

Make only high confidence suggestions when reviewing code changes.
Write code with good maintainability practices, including comments on why certain design decisions were made.
Handle edge cases and write clear exception handling.
For libraries or external dependencies, mention their usage and purpose in comments.

Use YAML files (application.yml) for externalized configuration.
Environment Profiles: Use Spring profiles for different environments (dev, test, prod)
Configuration Properties: Use @ConfigurationProperties for type-safe configuration binding
Secrets Management: Externalize secrets using environment variables or secret management systems

Package Structure: Organize by feature/domain rather than by layer
Separation of Concerns: Keep controllers thin, services focused, and repositories simple
Utility Classes: Make utility classes final with private constructors

Place business logic in @Service-annotated classes.
Services should be stateless and testable.
Inject repositories via the constructor.
Service method signatures should use domain IDs or DTOs, not expose repository entities directly unless necessary.

Use SLF4J for all logging (private static final Logger logger = LoggerFactory.getLogger(MyClass.class);).
Do not use concrete implementations (Logback, Log4j2) or System.out.println() directly.
Use parameterized logging: logger.info("User {} logged in", userId);.

Use parameterized queries | Always use Spring Data JPA or NamedParameterJdbcTemplate to prevent SQL injection.
Validate request bodies and parameters using JSR-380 (@NotNull, @Size, etc.) annotations and BindingResult

After adding or modifying code, verify the project continues to build successfully.
If the project uses Maven, run mvn clean install.
If the project uses Gradle, run ./gradlew build (or gradlew.bat build on Windows).
Ensure all tests pass as part of the build.