Chasing after another problem I found several blocked task threads, best as I can determine: InMemorySessionmanager$SessionImpl.invalidate() is invoked. This method is synchronized, and the call blocks inside SesssionListeners.sessionDestroyed() (separate issue there...) Later, InMemorySessionmanager$SessionImpl.bumpTimeout() is invoked from another thread. This method is also synchronized, and blocks waiting for invalidate() to complete. As the first thread is indefinitely blocked inside invalidate(), this second thread also remains blocked indefinitely. In my environment it appears to make an existing problem slightly more severe. Found in 1.1.0, but it looks like it's in both 1.1.7 and the master branch as well. Using RHEL, Java 7, Wildfly 8.2 invalidate() Thread trace (excerpt): * (blocked) - sun.misc.Unsafe.park(boolean, long) * ... * org.jboss.seam.contexts.ServletLifecycle.endSession(javax.servlet.http.HttpSession) (line: 187) * org.jboss.seam.servlet.SeamListener.sessionDestroyed(javax.servlet.http.HttpSessionEvent) (line: 59) * io.undertow.servlet.core.ApplicationListeners.sessionDestroyed(javax.servlet.http.HttpSession) (line: 264) * io.undertow.servlet.core.SessionListenerBridge.sessionDestroyed(io.undertow.server.session.Session, io.undertow.server.HttpServerExchange, io.undertow.server.session.SessionListener$SessionDestroyedReason) (line: 67) * io.undertow.server.session.SessionListeners.sessionDestroyed(io.undertow.server.session.Session, io.undertow.server.HttpServerExchange, io.undertow.server.session.SessionListener$SessionDestroyedReason) (line: 61) * io.undertow.server.session.InMemorySessionManager$SessionImpl.invalidate(io.undertow.server.HttpServerExchange, io.undertow.server.session.SessionListener$SessionDestroyedReason) (line: 413) * io.undertow.server.session.InMemorySessionManager$SessionImpl.invalidate(io.undertow.server.HttpServerExchange) (line: 399) * io.undertow.servlet.spec.HttpSessionImpl.invalidate() (line: 197) * ... bumpTimeout() Thread trace: * io.undertow.server.session.InMemorySessionManager$SessionImpl.bumpTimeout() (line: 271) * io.undertow.server.session.InMemorySessionManager$SessionImpl.getAttribute(java.lang.String) (line: 355) * io.undertow.servlet.util.SavedRequest.tryRestoreRequest(io.undertow.server.HttpServerExchange, javax.servlet.http.HttpSession) (line: 124) * io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 67) * io.undertow.security.handlers.SecurityInitialHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 76) * io.undertow.server.handlers.PredicateHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 43) * org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 61) * io.undertow.server.handlers.PredicateHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 43) * io.undertow.server.handlers.PredicateHandler.handleRequest(io.undertow.server.HttpServerExchange) (line: 43) * io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(io.undertow.server.HttpServerExchange, io.undertow.servlet.handlers.ServletChain, io.undertow.servlet.handlers.ServletRequestContext, javax.servlet.ServletRequest, javax.servlet.ServletResponse) (line: 261) * io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(io.undertow.server.HttpServerExchange, io.undertow.servlet.handlers.ServletRequestContext, io.undertow.servlet.handlers.ServletChain, javax.servlet.DispatcherType) (line: 247) * io.undertow.servlet.handlers.ServletInitialHandler.access$000(io.undertow.servlet.handlers.ServletInitialHandler, io.undertow.server.HttpServerExchange, io.undertow.servlet.handlers.ServletRequestContext, io.undertow.servlet.handlers.ServletChain, javax.servlet.DispatcherType) * io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(io.undertow.server.HttpServerExchange) (line: 166) * io.undertow.server.Connectors.executeRootHandler(io.undertow.server.HttpHandler, io.undertow.server.HttpServerExchange) (line: 197) * io.undertow.server.HttpServerExchange$1.run() (line: 759) * java.util.concurrent.ThreadPoolExecutor.runWorker(java.util.concurrent.ThreadPoolExecutor$Worker) (line: 1145) * java.util.concurrent.ThreadPoolExecutor$Worker.run() (line: 615) * java.lang.Thread.run() (line: 745) //EricP This message has been scanned for malware by Websense. www.websense.com