Tomcat 7 memory usage - what keeps it growing?

Good evening,

I've got an Apache Tomcat 7 running, with a little jsp for testing. Essentially, it just prints a few lines. Then, I've got a pla开发者_开发百科in html file with some text in it.

My question is: If I siege my Tomcat with ab it grows in memory, nothing special here. But the memory usage grows and grows without stopping. Moreover, it doesn't release it after a while. This happens with the jsp and the html.

Whats the reason for this behaviour?

Best regards

As @Bozho said its very likely a leak in code. Use jmap to see who is eating up so much of space.

jmap -histo:live <tomcat java process id>

This will show you which types of objects occupying how much memory in heap, that should give you idea which code to look into.