OperatorException: java.lang.NullPointerException
	at org.netbeans.jackpot.operator.Operator.error(Operator.java:97)
	at org.netbeans.jackpot.save.Commit.visitTopLevel(Commit.java:193)
	at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:450)
	at org.netbeans.jackpot.tree.NodeScanner.scan(NodeScanner.java:45)
	at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:43)
	at com.sun.tools.javac.tree.TreeScanner.visitPackageDef(TreeScanner.java:275)
	at com.sun.tools.javac.tree.JCTree$PackageDef.accept(JCTree.java:1846)
	at org.netbeans.jackpot.tree.NodeScanner.scan(NodeScanner.java:41)
	at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:43)
	at com.sun.tools.javac.tree.TreeScanner.visitPackageDef(TreeScanner.java:275)
	at com.sun.tools.javac.tree.JCTree$PackageDef.accept(JCTree.java:1846)
	at org.netbeans.jackpot.tree.NodeScanner.scan(NodeScanner.java:41)
	at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:43)
	at com.sun.tools.javac.tree.TreeScanner.visitPackageDef(TreeScanner.java:275)
	at com.sun.tools.javac.tree.JCTree$PackageDef.accept(JCTree.java:1846)
	at org.netbeans.jackpot.tree.NodeScanner.scan(NodeScanner.java:41)
	at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:43)
	at com.sun.tools.javac.tree.TreeScanner.visitPackageDef(TreeScanner.java:275)
	at com.sun.tools.javac.tree.JCTree$PackageDef.accept(JCTree.java:1846)
	at org.netbeans.jackpot.operator.Operator.apply(Operator.java:78)
	at org.netbeans.jackpot.save.Commit.apply(Commit.java:102)
	at org.netbeans.jackpot.Engine.commit(Engine.java:220)
	at org.netbeans.modules.jackpot.JackpotModule.releaseEngine(JackpotModule.java:140)
	at org.netbeans.modules.jackpot.JackpotModule.releaseEngine(JackpotModule.java:133)
	at org.netbeans.modules.jackpot.actions.StopEngineAction.performAction(StopEngineAction.java:54)
	at org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:94)
	at org.netbeans.modules.openide.util.ActionsBridge.doPerformAction(ActionsBridge.java:47)
	at org.openide.util.actions.CallableSystemAction.actionPerformed(CallableSystemAction.java:90)
	at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1957)
	at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2278)
	at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:377)
	at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:232)
	at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
	at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:1137)
	at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:1178)
	at java.awt.Component.processMouseEvent(Component.java:5955)
	at javax.swing.JComponent.processMouseEvent(JComponent.java:3282)
	at java.awt.Component.processEvent(Component.java:5720)
	at java.awt.Container.processEvent(Container.java:1960)
	at java.awt.Component.dispatchEventImpl(Component.java:4365)
	at java.awt.Container.dispatchEventImpl(Container.java:2018)
	at java.awt.Component.dispatchEvent(Component.java:4195)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4222)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3886)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3816)
	at java.awt.Container.dispatchEventImpl(Container.java:2004)
	at java.awt.Window.dispatchEventImpl(Window.java:2210)
	at java.awt.Component.dispatchEvent(Component.java:4195)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
[catch] 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)
Caused by: java.lang.NullPointerException
	at org.netbeans.jackpot.save.Commit.applyDiff(Commit.java:331)
	at org.netbeans.jackpot.save.Commit.commit(Commit.java:301)
	at org.netbeans.jackpot.save.Commit.visitTopLevel(Commit.java:162)
	... 53 more