A good profiler can help you find out what objects you have in memory, and what holds them from being garbage collected. We are using JProfiler, which is quite worth its money, in my opinion.
Do you put anything into sessions? You need to remember that your server doesn't notice when you close a browser, so the session will live on until you either destroy it programmatically (when the user explicitely logs out, for example), or it times out (which in
Tomcat, for example, happens after half an hour per default).
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus