Description of problem: org.rhq.core.pc.inventory.ResourceContainer In this code, the unlock() api [1] says it can throw an unchecked exception which would cause the TCCL to not be reset. if (this.lock != null) { this.lock.unlock(); } Thread.currentThread().setContextClassLoader(originalContextClassLoader); [1] http://download.oracle.com/javase/1,5.0/docs/api/java/util/concurrent/locks/Lock.html#unlock%28%29 We are seeing an issue which maybe be caused by this bug. JBoss server is started and there are some failed services that do not start when the server is started. The application seems to run fine with these failed services. After some unpredictable time, it seems the Admin Console tries to inventory services and hits these failed services which seems to be the precursor to the NoClassDef / ClassNotFound exceptions. We are trying to get test results with the admin console and failed services removed. Version-Release number of selected component (if applicable): JBoss EAP 5.1.0 deploy/admin-console.war/WEB-INF/lib/rhq-core-plugin-container.jar/org/rhq/core/pc/inventory/ResourceContainer.class From rhq-core-plugin-container.jar manifest: Implementation-Title: RHQ Plugin Container Implementation-Version: 3.0.0.EmbJopr2 Os-Version: 2.6.18-194.8.1.el5 How reproducible: Failed services such as HornetQ when starting JBoss. System runs for a while running tests against it. After some time, it seems the Admin Console tries to inventory services which we believe is the cause. If anyone knows how we might invoke inventory or try to trigger this, then we could confirm this is the issue.