Spring Boot Best Practices

Priority: P0

Implementation Guidelines

Dependency Injection (DI)

• Constructor Injection: ALWAYS use Constructor Injection for immutability. Use

  @RequiredArgsConstructor

  (Lombok) to reduce boilerplate. Mark all dependencies as

  final

  .
• Avoid @Autowired: NEVER use field injection. It prevents unit testing without Spring context and hides dependencies.

Configuration & Data

• Type-Safe Config: Use

  @ConfigurationProperties

  with Records (Java 17+) instead of

  @Value

  . Use Spring profile-specific files (e.g.,

  application-dev.yml

  ,

  application-prod.yml

  ) and set active profile via

  SPRING_PROFILES_ACTIVE

  . Never hardcode secret values in properties files.
• Validation: Combine with

  @Validated

  and Jakarta Bean Validation (

  @NotNull

  ,

  @NotEmpty

  ) to fail fast at startup. Use

  application.yaml

  for structured configuration.
• DTOs: Use

  records

  as immutable DTOs to reduce boilerplate and ensure thread safety. Handle empty values with

  Optional

  to avoid

  NullPointerException

  .

Observability & Quality

• Error Handling: Implement

  @ControllerAdvice

  and

  ProblemDetails

  (RFC 7807) for standardized error responses.
• Logging: Use

  SLF4J

  with

  @Slf4j

  . Implement Structured Logging by logging arguments (

  log.info("id: {}", id)

  ).
• Tooling: Mandate

  Spotless

  or

  Checkstyle

  for code formatting. Use

  sdkman

  to manage JDK 21+ versions.

Anti-Patterns

• No @Autowired on fields: Use constructor injection via @RequiredArgsConstructor.
• No Setters on dependencies: Declare all injected fields as final.
• No context.getBean(): Inject dependencies via constructor DI.
• No log-and-swallow: Rethrow or handle exceptions explicitly.

References

• Implementation Examples