4 Replies Latest reply on Aug 18, 2010 6:51 AM by jaikiran

Memory leak in StatelessBeanContext

delgurth Aug 11, 2010 7:18 AM

Our application starts a service (org.jboss.ejb3.annotation.Service) which uses java.util.TimerTask to start jobs.

These jobs are Stateless EJB's. Within the run method of the timer that is triggered we use InitialContext.doLookup("JNDI_NAME"); to lookup these EJB's and execute a method on them. Now unfortunately once the EJB is done processing, it's not removed from memory, so after a few days our application runs out of heap space.The objects that are created in the run method to be passed as a parameter to the EJB are not kept in memory.

The objects that are growing during time (according to eclipse MAT) are the StatelessContainers, and specific the ThreadLocalPool pool variable in them.These keep the link towards the EJB's which are started from the timers.

We are wondering why the StatelessContainers keep our EJB's in their pool, even though they are done processing (according to us). And we are mostly interested in how to solve this memory leak, since restarting our application server ever few days is not really an option.

Removing for example JTA (and all logic besides a log statement) from the EJB's doesn't help, they are still kept in memory. Also when we use EJB timers (@javax.ejb.Timeout) to start the EJB's we get the same result.

We are using: JBossAS 5.1.0, sun jdk 1.6.0_17 with -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled

1. Re: Memory leak in StatelessBeanContext

jaikiran Aug 11, 2010 12:19 PM (in response to delgurth)

Looks related to https://jira.jboss.org/browse/EJBTHREE-1330
Actions
2. Re: Memory leak in StatelessBeanContext

delgurth Aug 18, 2010 5:33 AM (in response to jaikiran)

Thank you, it indeed seems to be related

Adding:

@Pool(value=PoolDefaults.POOL_IMPLEMENTATION_STRICTMAX,maxSize=5000,timeout=10000)

to the StateLessBeans that are started from the timers seems to be helping.

Now with this I've probably discovered the root cause of our problem, someone added "instance" variables to a few StateLessBeans and they are now becoming NULL between method calls (as the are "supposed" to). That was not the case before I added the @Pool annotation.

-edit

That can't have been the root cause, since it was also happening to a simple StateLessBean without "instance" variables in it. So our real problem must be related to the issue that JBoss is not releasing those StateLessBeans even though it can (the strictmax pool doesn't cause any problems).
Actions
3. Re: Memory leak in StatelessBeanContext

delgurth Aug 18, 2010 6:22 AM (in response to delgurth)

B.T.W. the maxsize value doesn't seem to matter. Once I install this pool most StateLessBeans have only 1 instance. Which is, I.M.H.O., clearly an indicator that this is a bug.
Actions
4. Re: Memory leak in StatelessBeanContext

jaikiran Aug 18, 2010 6:51 AM (in response to delgurth)

Wessel van Norel wrote:

B.T.W. the maxsize value doesn't seem to matter. Once I install this pool most StateLessBeans have only 1 instance. Which is, I.M.H.O., clearly an indicator that this is a bug.
You mean maxsize for StrictMaxPool? Can you provide your bean code configurations. Also see if this helps http://docs.jboss.org/ejb3/docs/reference/1.0.7/html/SessionBean_and_MDB_configuration.html
Actions

Go to original post