Bugs item #823649, was opened at 2003-10-14 12:30 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=376685&aid=823649&group_id=22866
Category: JBossMX Group: v3.2 Status: Open Resolution: None Priority: 5 Submitted By: Peter Stout (stottos) Assigned to: Nobody/Anonymous (nobody) Summary: ConcurrentModificationException in UnifiedLoaderRepository3 Initial Comment: The getResourceFromRepository method in UnifiedLoaderRepository3 does not synchronize access to the packagesMap and classLoaders fields, unlike all other accesses to those fields. As a result, if classes are being loaded at the same time as a resource is being looked up, a ConcurrentModificationException can be triggered. I have attached a proposed patch for this bug. The fix wraps the uses of packagesMap and classLoaders fields in the appropriate synchronized blocks. If the all of the class loaders need to be searched, a copy of the classLoaders field is made to avoid having to synchronize while performing the search. The existing code is inconsistent in the way it makes a copy of the classLoaders field: new HashSet(classLoaders) versus classLoaders.clone(). I arbitrarily chose the former, but whoever fixes the bug might consider making the code consistent one way or the other. I suspect that there is a second order synchronization problem in the processing of any HashSet retrieved from the packagesMap. The retrieved HashSet may be concurrently modified if a class loader is added or removed while the set is being processed. The modifications to the HashSet's in the packagesMap performed in the add/remove class loader code path are performed while holding the packagesMap lock, but the code in getResourceFromRepository and LoadMgr3.beginLoadTask, which retrieves a package set using the getPackageClassLoaders method, is unsynchronized. Unless there is some other lock that makes this a non-issue, I suspect that fixing the problem will require either making a copy of the HashSet or a moderate amount of code restructuring. ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=376685&aid=823649&group_id=22866 ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. SourceForge.net hosts over 70,000 Open Source Projects. See the people who have HELPED US provide better services: Click here: http://sourceforge.net/supporters.php _______________________________________________ JBoss-Development mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/jboss-development
