java.lang.NullPointerException
        at org.netbeans.modules.java.editor.codegen.ImplementOverrideMethodGenerator$1.run(ImplementOverrideMethodGenerator.java:156)
        at org.netbeans.modules.java.editor.codegen.ImplementOverrideMethodGenerator$1.run(ImplementOverrideMethodGenerator.java:152)
        at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:910)
        at org.netbeans.modules.java.editor.codegen.ImplementOverrideMethodGenerator.invoke(ImplementOverrideMethodGenerator.java:151)
        at org.netbeans.modules.java.editor.codegen.ui.GenerateCodePanel.invokeSelected(GenerateCodePanel.java:149)
        at org.netbeans.modules.java.editor.codegen.ui.GenerateCodePanel.listKeyReleased(GenerateCodePanel.java:124)
        at org.netbeans.modules.java.editor.codegen.ui.GenerateCodePanel.access$000(GenerateCodePanel.java:61)
        at org.netbeans.modules.java.editor.codegen.ui.GenerateCodePanel$1.keyReleased(GenerateCodePanel.java:99)
        at java.awt.AWTEventMulticaster.keyReleased(AWTEventMulticaster.java:243)
        at java.awt.Component.processKeyEvent(Component.java:6002)
        at javax.swing.JComponent.processKeyEvent(JComponent.java:2799)
        at java.awt.Component.processEvent(Component.java:5818)
        at java.awt.Container.processEvent(Container.java:2058)
        at java.awt.Component.dispatchEventImpl(Component.java:4413)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
        at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:697)
        at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:962)
        at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:834)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:661)
        at java.awt.Component.dispatchEventImpl(Component.java:4285)
        at java.awt.Container.dispatchEventImpl(Container.java:2116)
        at java.awt.Window.dispatchEventImpl(Window.java:2440)
        at java.awt.Component.dispatchEvent(Component.java:4243)
        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)