java.lang.NullPointerException: The key parameter cannot be null
        at org.openide.util.Parameters.notNull(Parameters.java:86)
        at org.netbeans.core.output2.PairMap.add(PairMap.java:103)
        at org.netbeans.core.output2.NbIOProvider.getIO(NbIOProvider.java:118)
        at org.netbeans.core.output2.NbIOProvider.getIO(NbIOProvider.java:97)
        at org.netbeans.modules.j2ee.deployment.plugins.api.UISupport.getServerIO(UISupport.java:162)
        at org.netbeans.modules.j2ee.deployment.impl.ServerInstance.remove(ServerInstance.java:428)
        at org.netbeans.modules.j2ee.deployment.impl.ui.actions.RemoveInstanceAction.performAction(RemoveInstanceAction.java:73)
        at org.openide.util.actions.NodeAction$DelegateAction$1.run(NodeAction.java:589)
        at org.netbeans.modules.openide.util.ActionsBridge.implPerformAction(ActionsBridge.java:83)
        at org.netbeans.modules.openide.util.ActionsBridge.doPerformAction(ActionsBridge.java:64)
        at org.openide.util.actions.NodeAction$DelegateAction.actionPerformed(NodeAction.java:585)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
        at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1225)
        at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1266)
        at java.awt.Component.processMouseEvent(Component.java:6263)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6028)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:117)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)