501-frameworks-micronaut-core

# Micronaut Core Guidelines Apply Micronaut core guidelines for DI, configuration, HTTP adapters, and operations. **What is covered in this Skill?** - Thin `main` with `Micronaut.run(Application.class, args)` - Bean scopes: @Singleton, @Prototype; request scope only when justified - Constructor injection with `jakarta.inject.Inject` - @Factory for third-party or explicit bean construction - @ConfigurationProperties (grouped settings) vs scattered @Property - @Requires and environments instead of env branching in domain code - Thin @Controller types delegating to @Singleton services - @Scheduled with explicit failure visibility - @ExecuteOn(TaskExecutors.BLOCKING) (or virtual-thread executors) for blocking I/O off the event loop - Netty graceful shutdown properties - AOP interceptors for cross-cutting concerns **Scope:** Apply recommendations based on the reference rules and good/bad code examples. ## Constraints Before applying Micronaut 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 - **PREREQUISITE**: Project must compile successfully before applying Micronaut core improvements - **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 Micronaut application structure and beans - Apply best practices for Micronaut configuration, @Requires, and factories - Improve scheduling, shutdown, or threading in Micronaut services ## Workflow 1. **Read reference and assess project context** Read `references/501-frameworks-micronaut-core.md` and inspect the current project setup before proposing changes. 2. **Gather scope and decide target improvements** Identify requested outcomes, constraints, and the minimum safe set of changes to apply. 3. **Apply framework-aligned changes** Implement or refactor configuration/code following the reference patterns and project conventions. 4. **Run verification and report results** Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions. ## Reference For detailed guidance, examples, and constraints, see [references/501-frameworks-micronaut-core.md](references/501-frameworks-micronaut-core.md).