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:929)
   at com.sun.tools.jdi.PacketStream.send(PacketStream.java:41)
   at com.sun.tools.jdi.JDWP$ObjectReference$ReferenceType.enqueueCommand(JDWP.java:3900)
   at com.sun.tools.jdi.JDWP$ObjectReference$ReferenceType.process(JDWP.java:3886)
   at com.sun.tools.jdi.ObjectReferenceImpl.referenceType(ObjectReferenceImpl.java:134)
   at com.sun.tools.jdi.ObjectReferenceImpl.type(ObjectReferenceImpl.java:128)
   at org.netbeans.modules.debugger.jpda.models.AbstractVariable.getType(AbstractVariable.java:356)
   at org.netbeans.modules.debugger.jpda.ui.models.VariablesTreeModelFilter.getFilter(VariablesTreeModelFilter.java:483)
   at org.netbeans.modules.debugger.jpda.ui.models.VariablesTreeModelFilter.access$200(VariablesTreeModelFilter.java:57)
   at org.netbeans.modules.debugger.jpda.ui.models.VariablesTreeModelFilter$4.run(VariablesTreeModelFilter.java:304)
   at org.netbeans.modules.debugger.jpda.ui.models.VariablesTreeModelFilter.run(VariablesTreeModelFilter.java:136)
   at org.openide.util.Task.run(Task.java:207)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:469)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:870)