My web application use hibernate 2.0.2 which is running on Resin. After running for some time, it reports OutOfMemory error. I don't know where the memory leak is . I do close the session in finally clause in every servlet.

Any clue ?

Thanks

You have not posted nearly enough information for help. But, in web apps, this can typically be attributed to one of two things:

1) Storing a lot of references into session and/or application scope[/list]
2) Not giving the application enough memory to play with on startup (e.g., the default HotSpot setting on windows are a mere 32K).

When does hibernate release cached objects then ? After each session.close() ? Anyone can explain how hibernate's caching mechanism works internally ? Is it session oriented ?

If you are not utilizing the JCS caching, then yes. The objects cached within the session are released when the session is closed.

If you want them released sooner, you can explicitly do so with the evict() method.

Even when you are using JCS caching. Hibernate never caches actual persistent instances between sessions.