JVM Heap is fine, so why does memory blow up? — A Native Memory Deep Dive in Docker (Part 2)

This covers the phenomenon where, when running a JVM application in a Docker container environment, the container is terminated by the OOM (Out Of Memory) Killer even though the configured JVM Heap memory has room to spare.

The core of this issue lies in the usage of Native Memory, not the Heap area. Beyond the Heap, the JVM uses native memory in various areas such as Metaspace, Code Cache, Stack, and Direct Buffer.

In particular, within Docker's Cgroup memory limits, if this native memory usage exceeds the expected range, the entire container can be terminated. To prevent this, it is necessary to accurately understand the JVM's memory structure and configure an appropriate Memory Limit.