Java Tooling

---
name: java-tooling
description: Configure Maven, Gradle, and static analysis for Java projects. Use for Java-only build and quality tooling such as Spotless, Checkstyle, SpotBugs, SonarLint, JDK versions, and Java service Dockerfiles; defer Kotlin, Android, Flutter, and GitHub Actions-specific configuration.
metadata:
  triggers:
    files:
    - 'pom.xml'
    - 'build.gradle'
    - 'build.gradle.kts'
    - '.sdkmanrc'
    keywords:
    - mvnw
    - gradlew
    - spotbugs
    - checkstyle
    - spotless
    - eclipse-temurin
---
# Java Tooling Standards

## **Priority: P2 (MEDIUM)**


## Implementation Guidelines

- **JDK Setup**: Use **`.sdkmanrc`** or **`.java-version`** to lock project to **LTS Support (17 or 21)**. Configure Gradle toolchain via `java { toolchain { languageVersion = JavaLanguageVersion.of(21) } }` for reproducible builds.
- **Maven & Wrapper**: Use **`pom.xml`** with **`<dependencyManagement>`**. ALWAYS use **`mvnw`** wrapper.
- **Gradle & Catalog**: Prefer **`build.gradle.kts`** (Kotlin DSL) with **`libs.versions.toml`** (Version Catalog). Use **`gradlew`** wrapper.
- **Formatting**: Enforce **Google Style Guide** using **`Spotless`** (`googleJavaFormat()` plugin) or **`Checkstyle`**.
- **Static Analysis**: Integrate **`SpotBugs`** or **`SonarLint`** for deep analysis. Use **`Detekt`** if using Kotlin.
- **Docker**: Use **Multi-stage Dockerfiles**. Use **`eclipse-temurin`** as base image.
- **CI/CD**: Configure **GitHub Actions** or **GitLab CI** to run `mvnw test` or `gradlew build` on every PR.

## Anti-Patterns

- **No Global Installs**: Always use mvnw/gradlew wrappers; never rely on system Maven/Gradle.
- **No Fat Jars**: Prefer layered Docker images over uber-jars for better layer caching.
- **No Snapshots in Prod**: Never use -SNAPSHOT dependency versions in production builds.

## References

- [Gradle Kotlin DSL & Spotless Setup](references/example.md)