com.sun.jdi.VMDisconnectedException: connection is closed
        at com.sun.tools.jdi.TargetVM.send(TargetVM.java:274)
        at com.sun.tools.jdi.VirtualMachineImpl.sendToTarget(VirtualMachineImpl.java:1011)
        at com.sun.tools.jdi.PacketStream.send(PacketStream.java:41)
        at com.sun.tools.jdi.JDWP$EventRequest$Set.enqueueCommand(JDWP.java:6765)
        at com.sun.tools.jdi.JDWP$EventRequest$Set.process(JDWP.java:6735)
        at com.sun.tools.jdi.EventRequestManagerImpl$EventRequestImpl.set(EventRequestManagerImpl.java:179)
        at com.sun.tools.jdi.EventRequestManagerImpl$EventRequestImpl.setEnabled(EventRequestManagerImpl.java:143)
        at com.sun.tools.jdi.EventRequestManagerImpl$EventRequestImpl.enable(EventRequestManagerImpl.java:128)
        at org.netbeans.modules.debugger.jpda.models.ThreadsCache.setVirtualMachine(ThreadsCache.java:101)
        at org.netbeans.modules.debugger.jpda.models.ThreadsCache.<init>(ThreadsCache.java:88)
        at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.getThreadsCache(JPDADebuggerImpl.java:1296)
        at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.getAllThreads(JPDADebuggerImpl.java:1317)
        at org.netbeans.modules.debugger.jpda.ThreadsCollectorImpl.getAllThreads(ThreadsCollectorImpl.java:76)
        at org.netbeans.modules.debugger.jpda.ThreadsCollectorImpl.<init>(ThreadsCollectorImpl.java:69)
        at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.getThreadsCollector(JPDADebuggerImpl.java:1701)
        at org.netbeans.modules.debugger.jpda.ui.CurrentThreadAnnotationListener$AllThreadsAnnotator.<init>(CurrentThreadAnnotationListener.java:381)
        at org.netbeans.modules.debugger.jpda.ui.CurrentThreadAnnotationListener.updateCurrentDebugger(CurrentThreadAnnotationListener.java:140)
        at org.netbeans.modules.debugger.jpda.ui.CurrentThreadAnnotationListener.propertyChange(CurrentThreadAnnotationListener.java:101)
        at org.netbeans.api.debugger.DebuggerManager.firePropertyChange(DebuggerManager.java:674)
        at org.netbeans.api.debugger.DebuggerManager.setCurrentSession(DebuggerManager.java:468)
        at org.netbeans.api.debugger.DebuggerManager.startDebugging(DebuggerManager.java:405)
        at org.netbeans.api.debugger.jpda.JPDADebugger.startListening(JPDADebugger.java:218)
        at org.netbeans.modules.debugger.jpda.ant.JPDAStart$1.run(JPDAStart.java:324)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)