PermGen Removal: The End of a Classic Error OutOfMemoryError: PermGen space was the Java error that launched a thousand Stack Overflow questions. Application servers would run fine for hours and then fall over during a hot redeploy. The fix — adding more -XX:MaxPermSize — was a band-aid. Java 8 removed the underlying problem entirely. Before Java 8, the JVM heap was divided into several regions. One of them — Permanent Generation (PermGen) — held class metadata, interned strings, and bytecode.