java-development

Java Development Agent

Router skill for general Java/JVM work. Treat Spring Boot as one supported framework, not the default for every project. Load only the matching rule files below.

Defaults

• Output explanations in Chinese when the user uses Chinese; keep code unchanged unless editing.
• First identify the current project's runtime, Java version, build tool, framework, test stack, and conventions. Existing evidence beats this skill's defaults.
• Do not introduce Spring Boot, Maven, Gradle, Lombok, MyBatis-Plus, JPA, Testcontainers, or Java 17+ syntax unless the project already uses it or the user asks.
• If creating a new project and no preference is given: choose a dependency-supported Java LTS baseline (17 or newer), infer Maven or Gradle from the surrounding repository, use JUnit 5, constructor-based design, SLF4J-compatible logging, and immutable DTOs where practical.
• For a new Spring Boot project, verify the current stable release, Java/build requirements, and third-party starter compatibility from official sources before choosing a line. For existing projects, keep their supported line unless migration is requested.
• Do not choose a persistence framework by geography or popularity. Preserve the existing choice; for greenfield work, select JDBC, jOOQ, MyBatis/MyBatis-Plus, or JPA/Hibernate from the actual query model and team constraints.
• Prefer constructor injection in DI frameworks. Use Lombok (@RequiredArgsConstructor, @Slf4j) only when the project already uses Lombok; otherwise write explicit constructors/loggers.
• If multiple modules or frameworks exist, modify only the affected module unless the user asks for a cross-cutting change.
• Do not edit generated output unless explicitly requested; edit the source template, annotation processor input, schema, or generator configuration instead.

Loading Rules

Start with the smallest useful set:

• Any Java task: load core/java-general-development.md only if project classification or default choice is unclear.
• API/exception/version work: load the specific core/... rule before framework rules.
• Build edits: load exactly one build rule (build-tools/...) matching the detected build tool.
• Spring Boot edits: load the primary spring-boot/... rule only when the project actually uses Spring Boot.
• Broad code review: start with code-review/cr-anti-patterns.md, then add specific risk files.
• Test work: load testing/test-layering.md first, then the framework-specific test file.
• JVM incident: load the symptom file first; add GC/thread/resource files only when evidence points there.
• Do not load README files or examples/ unless the user asks for usage docs.