In NetBeans when you try to close an output tab, you get the following exception:

java.lang.ArrayIndexOutOfBoundsException: 1 >= 1
    at java.util.Vector.elementAt(Vector.java:431)
    at javax.swing.JTabbedPane.getComponentAt(JTabbedPane.java:1201)
    at javax.swing.JTabbedPane.getSelectedComponent(JTabbedPane.java:637)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane.sel(CloseButtonTabbedPane.java:58)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane.access$200(CloseButtonTabbedPane.java:38)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane$CBTPPolicy.getDefaultComponent(CloseButtonTabbedPane.java:80)
    at javax.swing.SortingFocusTraversalPolicy.enumerateAndSortCycle(SortingFocusTraversalPolicy.java:131)
    at javax.swing.SortingFocusTraversalPolicy.getComponentAfter(SortingFocusTraversalPolicy.java:244)
    at javax.swing.LayoutFocusTraversalPolicy.getComponentAfter(LayoutFocusTraversalPolicy.java:88)
    at java.awt.Container.nextFocusHelper(Container.java:3076)
    at java.awt.Component.removeNotify(Component.java:6459)
    at java.awt.Container.removeNotify(Container.java:2551)
    at javax.swing.JComponent.removeNotify(JComponent.java:4624)
    at javax.swing.text.JTextComponent.removeNotify(JTextComponent.java:1623)
    at java.awt.Container.removeNotify(Container.java:2545)
    at javax.swing.JComponent.removeNotify(JComponent.java:4624)
    at java.awt.Container.removeNotify(Container.java:2545)
    at javax.swing.JComponent.removeNotify(JComponent.java:4624)
    at java.awt.Container.removeNotify(Container.java:2545)
    at javax.swing.JComponent.removeNotify(JComponent.java:4624)
    at org.netbeans.core.output2.OutputTab.removeNotify(OutputTab.java:49)
    at java.awt.Container.remove(Container.java:1123)
    at javax.swing.JTabbedPane.removeTabAt(JTabbedPane.java:955)
    at javax.swing.JTabbedPane.remove(JTabbedPane.java:1003)
    at org.netbeans.core.output2.ui.AbstractOutputWindow.remove(AbstractOutputWindow.java:141)
    at org.netbeans.core.output2.Controller.close(Controller.java:557)
    at org.netbeans.core.output2.OutputWindow.closeRequest(OutputWindow.java:60)
    at org.netbeans.core.output2.ui.AbstractOutputWindow.propertyChange(AbstractOutputWindow.java:54)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:347)
    at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
    at java.awt.Component.firePropertyChange(Component.java:7802)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane.fireCloseRequest(CloseButtonTabbedPane.java:278)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane.access$800(CloseButtonTabbedPane.java:38)
    at org.netbeans.core.output2.ui.CloseButtonTabbedPane$CloseButtonListener.eventDispatched(CloseButtonTabbedPane.java:377)
    at java.awt.Toolkit$SelectiveAWTEventListener.eventDispatched(Toolkit.java:2360)
    at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2252)
    at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2251)
    at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2251)
    at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2251)
    at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2251)
    at java.awt.Toolkit.notifyAWTEventListeners(Toolkit.java:2210)
    at java.awt.Component.dispatchEventImpl(Component.java:4305)
    at java.awt.Container.dispatchEventImpl(Container.java:2042)
    at java.awt.Component.dispatchEvent(Component.java:4237)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4248)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3912)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3842)
    at java.awt.Container.dispatchEventImpl(Container.java:2028)
    at java.awt.Window.dispatchEventImpl(Window.java:2300)
    at java.awt.Component.dispatchEvent(Component.java:4237)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)

This is likely the result of NetBeans trying to work around the problem that has now been solved by 6368047. Perhaps their code doesn't work well with our fix.