Did you find what was the reason?
I am having exactly same problem at the moment. And can't yet profile what exactly is allocating the objects.
I don't think I have something wrong in my Application Logic.
Are the number of instances increasing during the time?
You should check via visualGC or jstat (all from java homepage) whether the memory consumption increase.
If increase linear with load it looks like an application problem.
I am having the same issue, recently i took the dump of Jboss and found that there are 10510222 instances of SimpleRole object.
I am using jboss 5.1. Do you know the reason behind this ?
first, it is better to create a new thread instead of reactivating such old one
But you are on the half way
What is SimpleRole object? Your code?
Search along the path and find the owner of that object, often it is a STATELESS session bean that hold some static variables and here are references to old objects that are never garbaged in that case.