java.lang.NullPointerException
        at org.netbeans.modules.settings.convertors.SerialDataConvertor$SaveSupport.access$200(SerialDataConvertor.java:523)
        at org.netbeans.modules.settings.convertors.SerialDataConvertor.run(SerialDataConvertor.java:344)
        at org.netbeans.modules.settings.ScheduledRequest.performRequest(ScheduledRequest.java:197)
        at org.netbeans.modules.settings.ScheduledRequest.runAndWait(ScheduledRequest.java:135)
        at org.netbeans.modules.settings.convertors.SerialDataConvertor$SaveSupport.save(SerialDataConvertor.java:820)
        at org.openide.loaders.InstanceDataObject.dispose(InstanceDataObject.java:1006)
        at org.openide.loaders.DataObject.markInvalid0(DataObject.java:214)
        at org.openide.loaders.MultiDataObject.notifyFileDeleted(MultiDataObject.java:1234)
        at org.openide.loaders.DataObjectPool$FSListener.fileDeleted(DataObjectPool.java:633)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEventImpl(FCLSupport.java:139)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEvent(FCLSupport.java:122)
        at org.openide.filesystems.FCLSupport.dispatchEvent(FCLSupport.java:99)
        at org.openide.filesystems.FileObject$ED.dispatch(FileObject.java:953)
        at org.openide.filesystems.EventControl.invokeDispatchers(EventControl.java:203)
        at org.openide.filesystems.EventControl.exitAtomicAction(EventControl.java:177)
        at org.openide.filesystems.EventControl.runAtomicAction(EventControl.java:122)
        at org.openide.filesystems.FileSystem.runAtomicAction(FileSystem.java:502)
        at org.openide.loaders.DataObjectPool.runAtomicAction(DataObjectPool.java:270)
        at org.openide.loaders.DataObject.invokeAtomicAction(DataObject.java:869)
        at org.openide.loaders.DataObject.delete(DataObject.java:606)
        at org.netbeans.core.windows.persistence.PersistenceManager.saveTopComponents(PersistenceManager.java:796)
        at org.netbeans.core.windows.persistence.PersistenceManager.saveWindowSystem(PersistenceManager.java:1134)
        at org.netbeans.core.windows.PersistenceHandler.save(PersistenceHandler.java:307)
        at org.netbeans.core.windows.WindowSystemImpl.save(WindowSystemImpl.java:76)
        at org.netbeans.core.NbTopManager$2.run(NbTopManager.java:380)
        at org.netbeans.ModuleManager.shutDown(ModuleManager.java:1567)
        at org.netbeans.core.startup.ModuleSystem.shutDown(ModuleSystem.java:291)
        at org.netbeans.core.NbTopManager.doExit(NbTopManager.java:389)
        at org.netbeans.core.NbTopManager.exit(NbTopManager.java:345)
        at org.netbeans.core.NbTopManager$NbLifecycleManager.exit(NbTopManager.java:441)
        at org.netbeans.core.windows.view.ui.MainWindow$3.windowClosing(MainWindow.java:330)
        at java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:291)
        at java.awt.Window.processWindowEvent(Window.java:1203)
        at javax.swing.JFrame.processWindowEvent(JFrame.java:266)
        at java.awt.Window.processEvent(Window.java:1161)
        at java.awt.Component.dispatchEventImpl(Component.java:3984)
        at java.awt.Container.dispatchEventImpl(Container.java:2024)
        at java.awt.Window.dispatchEventImpl(Window.java:1791)
        at java.awt.Component.dispatchEvent(Component.java:3819)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:463)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)