We also discussed with other people that are developing using Servoy and the heap memory for their solutions looks similar with ours, while they have a much low memory for the java process, as the OS displays.It would be more interesting to learn which OS, which JVM version and which servlet container / application server they use. That opens up the possibility for you to test in a similar environment to see if that changes anything.
We also thought that there might be some leaks in the app, but those leaks would be visible in the heap memory.Not if the leak is in a native module (DLL, so), that is memory managed outside of the JVM.
bogdan wrote:If you are certain that there are absolutely no native (jni) code in anything that you are running then that is, by definition, a jvm bug.
then it crashes in at most few days, sometimes in few hours or even less.