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.

Spring Boot Instructions

Dependency Injection

Use constructor injection for all required dependencies.
Declare dependency fields as private final.

Configuration

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

Code Organization

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

Service Layer

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.

Logging

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);.

Security & Input Handling

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

Build and Verification

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

Useful Commands

Gradle Command	Maven Command	Description
`./gradlew bootRun`	`./mvnw spring-boot:run`	Run the application.
`./gradlew build`	`./mvnw package`	Build the application.
`./gradlew test`	`./mvnw test`	Run tests.
`./gradlew bootJar`	`./mvnw spring-boot:repackage`	Package the application as a JAR.
`./gradlew bootBuildImage`	`./mvnw spring-boot:build-image`	Package the application as a container image.

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.

Spring Boot Instructions

Dependency Injection

Use constructor injection for all required dependencies.

Declare dependency fields as private final.

Configuration

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

Code Organization

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

Service Layer

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.

Logging

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);.

Security & Input Handling

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

Useful Commands

Gradle Command	Maven Command	Description
`./gradlew bootRun`	`./mvnw spring-boot:run`	Run the application.
`./gradlew build`	`./mvnw package`	Build the application.
`./gradlew test`	`./mvnw test`	Run tests.
`./gradlew bootJar`	`./mvnw spring-boot:repackage`	Package the application as a JAR.
`./gradlew bootBuildImage`	`./mvnw spring-boot:build-image`	Package the application as a container image.

Spring Boot Development