Stefan Will wrote:
Yes, I think the JVM uses way more memory than just its heap. Now some of it might be just reserved memory, but not actually used (not sure how to tell the difference). There are also things like thread stacks, jit compiler cache, direct nio byte buffers etc. that take up process space outside of the Java heap. But none of that should imho add up to Gigabytes...
good article on this http://www.ibm.com/developerworks/linux/library/j-nativememory-linux/