State-of-the-art JVM engineering rules (2026 baseline) for Java and Kotlin that Claude applies when writing or auditing JVM code. Baseline Java 25 LTS (virtual threads final since 21; structured concurrency still preview), Kotlin 2.x. Covers modern idioms (records, sealed types, pattern matching, Ko
State-of-the-art JVM engineering rules (2026 baseline) for Java and Kotlin that Claude applies when writing or auditing JVM code. Baseline Java 25 LTS (virtual threads final since 21; structured concurrency still preview), Kotlin 2.x. Covers modern idioms (records, sealed types, pattern matching, Kotlin null-safety/coroutines), API/null/immutability design, concurrency (virtual threads, JMM, java.