How to clear permgen memory space

Question

I am using MAT to analyze memory.

Size: 14.4 MB Classes: 7k Objects: 350.9k Class Loader: 116

I\'ve got the above report using MAT memory analyz

Answer 1

As far as I know there is no function that clears permgen. On default, jvm holds all the loaded classes indefinitely. But you can change this behaviour using -XX:+CMSClassUnloadingEnabled and -XX:+UseConcMarkSweepGC parameters.

If you use CMSClassUnloadingEnabled parameter the GC will also sweep PermGen and remove classes which are no longer used.