[ http://issues.apache.org/jira/browse/HIVEMIND-161?page=comments#action_12359377 ]
Kyrill Alyoshin commented on HIVEMIND-161: ------------------------------------------ It'd be nice to know what your fix was, Carman. :-) Anyway, the point is that there is a private ThreadLocal variable (in particular "_storage" variable in ThreadEventNotifierImpl) that is never "cleaned up" in that object. (There is simply nothing that does "_storage.set(null);" in that class); therefore, this Thread (i.e. an object loaded by System classloader) will always contain strong references to objects stored in "_storage" and, as a result, WebappClassLoader will never be garbage collected along with everything it points to. Howard said he's gonna look into it in a couple of days once he settles in his new home on the west coast. > ThreadLocal object is never removed in ThreadEventNotifierImpl and holds the > classloader > ---------------------------------------------------------------------------------------- > > Key: HIVEMIND-161 > URL: http://issues.apache.org/jira/browse/HIVEMIND-161 > Project: HiveMind > Type: Bug > Components: framework > Versions: 1.1 > Environment: Tomcat 5.5.12, J2SE 1.6 Mustang build 62, Win XP SP2 > Reporter: Kyrill Alyoshin > Priority: Critical > Attachments: hivemind-threadlocals.pdf > > The following prevents the web application classloader from being garbage > collected on hot redeploys of web applications. > Please note that the issue is present on J2SE 1.5 as well. I use 1.6 only > because it has far better support for JVMTI and as such the issue was easy to > discover with YourKit profiler. Here it is: > 1. org.apache.hivemind.service.impl.ThreadEventNotifierImpl puts > EventListenerList ("list" variable) on its private ThreadLocal "_storage" > variable in addThreadCleanupListener method. > 2. No where in that class does the actual list gets removed from ThreadLocal. > Thus, the WebappClassLoader cannot be garbage collected because one of the > object that it loaded (i.e. EventListenerList) is strongly referenced by live > threads in the container, which leads to huge memory leaks on hot-redeploys. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
