writing-java-kotlin

description

Idiomatic modern Java and Kotlin JVM development. Use when writing `.java`, `.kt`, or `.kts` code; changing Gradle or Maven builds; or working on Spring, Micronaut, Quarkus, Ktor, Android JVM modules, JUnit, Mockito, Kotest, ktlint, detekt, or JVM CLI/services. Emphasizes JDK toolchains, null-safety, fast focused Gradle/Maven feedback, deterministic formatting, and minimal dependencies. NOT for JavaScript/TypeScript, C#/.NET, Python, shell scripts, or infra-only work.

name

writing-java-kotlin

Java and Kotlin Development

Use only for Java/Kotlin JVM code and JVM build files. Follow the project's JDK, Kotlin, Gradle/Maven, framework, test stack, formatter, static-analysis config, and local conventions.

Read First

Read principles.md before writing, changing, or reviewing Java/Kotlin code. Read conditional references only when the change touches that area.

Conditional References

• patterns.md — package/module layout, Spring/Ktor/service boundaries, nullability, concurrency, persistence, and build seams.
• testing.md — adding or reshaping JUnit, Kotest, Mockito/MockK, Spring, or Gradle/Maven tests; keep the local loop fast.
• linting.md — Gradle/Maven toolchains, formatters, ktlint, detekt, Spotless, and slow-check policy.
• cli.md — writing or changing JVM CLIs.

Project Baseline

• Inspect gradle/wrapper/gradle-wrapper.properties, settings.gradle*, , , , , CI, and nearby code before using version-specific Java, Kotlin, or plugin behavior.