java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThread)
        at java.security.AccessControlContext.checkPermission(AccessControlContext.java:264)
        at java.security.AccessController.checkPermission(AccessController.java:427)
        at java.util.concurrent.ThreadPoolExecutor.shutdown(ThreadPoolExecutor.java:893)
        at java.util.concurrent.Executors$DelegatedExecutorService.shutdown(Executors.java:594)
        at org.jivesoftware.smack.PacketReader.shutdown(PacketReader.java:191)
        at org.jivesoftware.smack.XMPPConnection.shutdown(XMPPConnection.java:570)
        at org.jivesoftware.smack.XMPPConnection.disconnect(XMPPConnection.java:643)
        at org.jivesoftware.smack.XMPPConnection.disconnect(XMPPConnection.java:618)
        at org.netbeans.modules.kenai.collab.chat.KenaiConnection$1.run(KenaiConnection.java:280)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:573)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1005)