Spring Boot Core Guidelines

Apply Spring Boot Core guidelines for annotations, bean management, configuration, and dependency injection.

What is covered in this Skill?

• @SpringBootApplication and main application class
• Component annotations: @RestController, @Service, @Repository
• Bean definition, scoping, lifecycle
• Configuration classes and @ConfigurationProperties (with @Validated for fail-fast startup)
• Component scanning and package organization
• Conditional configuration and profiles (@Profile, @ConditionalOn*)
• Constructor dependency injection
• @Primary and @Qualifier for disambiguation when multiple beans share a type
• Bean minimization and composition
• Graceful shutdown for in-flight work
• Virtual threads on supported stacks for concurrency-bound workloads
• Jakarta EE namespace consistency (jakarta.* preferred; avoid mixing legacy javax.annotation / javax.validation)
• Scheduled tasks and background processing

Scope: Apply recommendations based on the reference rules and good/bad code examples.

Constraints

Before applying any Spring Boot changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification.

• MANDATORY: Run ./mvnw compile or mvn compile before applying any change
• SAFETY: If compilation fails, stop immediately — compilation failure is a blocking condition
• VERIFY: Run ./mvnw clean verify or mvn clean verify after applying improvements
• BEFORE APPLYING: Read the reference for detailed rules, good/bad patterns, and constraints

When to use this skill

• Review Java code for Spring Boot application
• Apply best practices for Spring Boot application in Java code

Reference

For detailed guidance, examples, and constraints, see references/301-frameworks-spring-boot-core.md.