java.lang.NullPointerException
        at javax.swing.JList$1.getSize(JList.java:425)
        at javax.swing.plaf.basic.BasicListUI.updateLayoutState(BasicListUI.java:1323)
        at javax.swing.plaf.basic.BasicListUI.maybeUpdateLayoutState(BasicListUI.java:1292)
        at javax.swing.plaf.basic.BasicListUI.getPreferredSize(BasicListUI.java:559)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1632)
        at javax.swing.ScrollPaneLayout.layoutContainer(ScrollPaneLayout.java:769)
        at java.awt.Container.layout(Container.java:1432)
        at java.awt.Container.doLayout(Container.java:1421)
        at java.awt.Container.validateTree(Container.java:1519)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validateTree(Container.java:1526)
        at java.awt.Container.validate(Container.java:1491)
        at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:635)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:127)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:177)
        at java.awt.Dialog$1.run(Dialog.java:1039)
        at java.awt.Dialog$3.run(Dialog.java:1091)
        at java.security.AccessController.doPrivileged(AccessController.java:0)
        at java.awt.Dialog.show(Dialog.java:1089)
        at org.netbeans.core.windows.services.NbPresenter.superShow(NbPresenter.java:834)
        at org.netbeans.core.windows.services.NbPresenter.doShow(NbPresenter.java:868)
        at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:856)
        at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:104)
        at org.openide.util.Mutex$1AWTWorker.run(Mutex.java:1238)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:199)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        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)