> On 03/03/2010 21:12, Sylvain Laurent wrote: > > > 3) a couple of months ago I had proposed on this very list a kind of memory > > leak protection > for those leaks caused by threads with incorrect CCL. I called this the > ExpendableClassLoader. > Please have a look at my post back then : > http://mail-archives.apache.org/mod_mbox/tomcat-dev/200903.mbox/%3cb1be8ffd-f13f-4b2b-b25a-83f2f855b...@m4x.org%3e > > Since I did not get any feedback about this idea at all, neither positive > > nor negative, > I can only assume that my post got lost in the middle of the other ones. I > still think that > this ExpendableClassLoader would improve the memory leak protection. Actually > it would make > the JreMemoryLeakPreventionListener useless and developers would not have to > think about which > option of the JreMemoryLeakPreventionListener is useful to them. > I suspect the lack of full source code (the Tomcat lists drop > attachments) had something to do with it. The concept sounds promising > and would be better than continually adding to the > JreLeakPreventionListener.
Should I try to pursue my investigation and provide a patch ? for TC 6 or 7 ? > > > 4) Not tomcat specific, but it might interest you anyways : > > there's definitely a problem with Sun's server VM, even with the latest > > 6.0_18. Classloaders > are not always collected by the GC and this can lead to an OOME in the perm > gen. I managed > to reproduce this with tomcat 6.0.24 and the petcare.war sample of Spring 3. > When using the > client VM, the WebAppClassLoader is always correctly GCed. When using the > server VM (either > 32 or 64 bits, on Windows or MacOS), the classloader is not collected and > after a couple of > redeployments, the perm gen is full and an OOME is raised. When analyzing the > heap dump, I > can see several instances of WebAppClassLoaders, and eclipse MAT > (www.eclipse.org/mat) shows > that there's no strong reference to them :-((( > That sounds like http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6916498 No, it's actually much more severe. The bug you filed provokes a one time leak: only the first webapp that uses DocumentBuilderFactory.newInstance().newDocumentBuilder() will leak. The bug I see with the server VM is probably closer to http://bugs.sun.com/view_bug.do?bug_id=4957990 which is supposed to be fixed since 6.0u16, but the comment of 2009-12-09 says otherwise. Anyways, I filed a bug report to Sun, it's in review for now... Sylvain --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
