Cursor-rules-java 501-frameworks-micronaut-core

Use when building or reviewing Micronaut applications — Micronaut.run bootstrap, @Singleton/@Prototype, @Factory beans, @ConfigurationProperties, environments, @Requires, @Controller vs services, @Scheduled, graceful shutdown, @ExecuteOn for blocking work, and Jakarta-consistent APIs. Part of the skills-for-java project

install

source · Clone the upstream repo

git clone https://github.com/jabrena/cursor-rules-java

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/jabrena/cursor-rules-java "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/501-frameworks-micronaut-core" ~/.claude/skills/jabrena-cursor-rules-java-501-frameworks-micronaut-core && rm -rf "$T"

manifest: skills/501-frameworks-micronaut-core/SKILL.md

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

Reference

For detailed guidance, examples, and constraints, see references/501-frameworks-micronaut-core.md.