JVM Internals in Containers: Why Heap Monitoring Isn't Enough

A JVM microservice in Kubernetes faced pod restarts despite healthy heap usage, because native memory from Metaspace, thread stacks, and direct buffers exceeded container limits. The article explains how JVM memory layout, classloading, and GC behavior differ in containerized environments versus traditional deployments. Understanding these internals is critical for building reliable cloud-native integration services.