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From Kevin Sutter <>
Subject Re: Memory Leak and JJCalls
Date Tue, 26 May 2009 15:29:24 GMT
Hi Mauro,
Hmmm...  There can be a lots of reasons for memory leaks.  I am not aware of
any memory leaks in the OpenJPA code at this time, but that doesn't mean
that some are not still waiting to be discovered...

First off, the jpql package that you reference is used for parsing the JPQL
that is being used by your application.  I'd very surpised if this package
was the culprit of the memory leak.  More than likely, this is due to some
references that are not being cleaned up properly.  Normally, memory
analysis tools will allow you to go "up the stack" and see where the
references are coming from.  Any other hints in this area?

OpenJPA provides a Query Compilation Cache that is on by default.  This
cache is for caching the parsed aspects of JPQL so that we don't have to
parse the same strings over and over again.  But, if this cache was getting
too large, you would see a different Class referenced in your memory

What version of OpenJPA are you using?  There have been various improvements
through out the lifetime of OpenJPA related to memory usage, locking,
threading, etc that may come into play with your scenario.

You mention that you are using Container-managed persistence. Which
application server are you using?  A common problem with Application-managed
persistence is not cleaning up the EntityManagers properly (thus causing
memory leaks).  I suppose it's possible that the Container-managed
persistence you are using has a problem with your scenario.

Let's start the conversation and see where it takes us.


On Mon, May 25, 2009 at 5:13 PM, Mauro Flores <> wrote:

> Hi,
> I'm getting memory leak in my aplication server. When I use a tool to see
> which object has more instances in memory, I find this class in the top
> five: org.apache.openjpa.kernel.jpql.JPQL$JJCalls.
> From this information, is it possible to imply that I not working correctly
> with JPA api, and this could be the reason of mem leak?
> My EntityManagers are managed by EJB. I don't opened neither close it.
> Thanks for some hint,
> Mauro.
> --
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