PermGen Out of Memory reasons

Question

I constantly detect OOM in PermGen for my environment:

1. java 6
2. jboss-4.2.3
3. Not a big web-application

I know about String.intern

Answer 1

You typically get this error when redeploying an application while having a classloader leak, because it means all your classes are loaded again while the old versions stay around.

There are two solutions:

• Restart the app server instead of redeploying the application - easy, but annoying
• Investigate and fix the leak using a profiler. Unfortunately, classloader leaks can be very hard to pinpoint.