What is perm space

From: http://stackoverflow.com/questions/1279449/what-is-perm-space
It stands for permanent generation:
The permanent generation is special because it holds meta-data describing user classes (classes that are not part of the Java language). Examples of such meta-data are objects describing classes and methods and they are stored in the Permanent Generation. Applications with large code-base can quickly fill up this segment of the heap which will cause java.lang.OutOfMemoryError : PermGen no matter how high your -Xmx and how much memory you have on the machine.