401-frameworks-quarkus-core

# Quarkus Core Guidelines Apply Quarkus core guidelines for CDI beans, configuration, profiles, and lifecycle. **What is covered in this Skill?** - @QuarkusMain and application entry (when custom main is needed) - CDI scopes: @ApplicationScoped, @Singleton, @Dependent; bean disambiguation (@Default, @Alternative, @Named) - Constructor injection with @Inject - CDI interceptors (@Interceptor, @InterceptorBinding) for cross-cutting concerns - CDI events: @Observes StartupEvent / ShutdownEvent, @ObservesAsync for async dispatch - Programmatic injection with Instance<T> for dynamic bean selection - @ConfigMapping and structured configuration with Bean Validation (@Valid) - Profile-specific properties (%dev, %test, %prod) and @IfBuildProfile - Startup and shutdown observers (@Startup, @PreDestroy) - Virtual threads with @RunOnVirtualThread (Java 21+) - Native-image safety: @RegisterForReflection, @DisabledOnNativeImage **Scope:** Apply recommendations based on the reference rules and good/bad code examples. ## Constraints Before applying any Quarkus 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 Quarkus core improvements - **SAFETY**: If compilation fails, stop immediately — compilation failure is a blocking condition - **BLOCKING CONDITION**: Compilation errors must be resolved by the user before proceeding - **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 Quarkus application structure and CDI - Apply best practices for Quarkus configuration and beans - Improve CDI interceptors, events, or programmatic injection in Quarkus - Add virtual-thread configuration or tune CDI lifecycle ## Workflow 1. **Read reference and assess project context** Read `references/401-frameworks-quarkus-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/401-frameworks-quarkus-core.md](references/401-frameworks-quarkus-core.md).