[rules-users] How and when are objects released in Stateless Session

Hi, can someone please explain; if a stateless session is used over a log period of time. How are the objects (rather the shadows to them) released? I understand that as long as a class is not final, its shadow is created and used. This raises a concern about the life cycle of that object. perhaps the cause of memory leaks in the past. Wanted to nkow the life cycle in breif. Thanks