mir-backend-jvm

Make It Right (JVM runtime tier). Java 21+ / Kotlin runtime reliability footguns shared across EVERY JVM backend framework (Spring Boot, Quarkus, Micronaut, Vert.x) — distinct from the generic backend gates and from any one framework's mechanics. Covers: thread-pool sizing and pool-exhaustion deadlock, blocking I/O on platform threads, Java 21 virtual threads and carrier-thread pinning inside synchronized/native calls, GC pause tuning (G1 vs ZGC/Shenandoah), container-aware heap sizing (-XX:MaxRAMPercentage vs hard -Xmx), cold-start / JIT warmup cost and mitigations (GraalVM native image, CRaC, AOT), shared-mutable-state visibility (happens-before, volatile, final, data races), and ThreadLocal leaks in pooled threads. TRIGGER when the backend runtime is Java or Kotlin — sits between mir-backend (generic gates) and the framework module (e.g. mir-backend-jvm-spring). SKIP for Python, Node, Go, Rust, .NET, Ruby, PHP, BEAM runtimes (each has its own mir-backend-<runtime> tier), and for framework-library mechanics (those live in the framework module).