Quarkus Core Guidelines

• @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)
• SmallRye Health probes (@Liveness, @Readiness)
• Virtual threads with @RunOnVirtualThread (Java 21+)
• Native-image safety: @RegisterForReflection, @DisabledOnNativeImage

Constraints

• 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 SmallRye Health probes or virtual-thread configuration

Reference