java.lang.AssertionError
   at org.netbeans.modules.java.api.common.project.BaseActionProvider.invokeAction(BaseActionProvider.java:388)
   at org.netbeans.spi.project.support.LookupProviderSupport$MergedActionProvider.invokeAction(LookupProviderSupport.java:261)
   at org.netbeans.modules.java.j2seproject.ui.customizer.J2SEProjectProperties$2.run(J2SEProjectProperties.java:466)
   at org.netbeans.modules.java.j2seproject.ui.customizer.J2SEProjectProperties$2.run(J2SEProjectProperties.java:443)
   at org.openide.util.Mutex.writeAccess(Mutex.java:436)
   at org.netbeans.modules.java.j2seproject.ui.customizer.J2SEProjectProperties.save(J2SEProjectProperties.java:443)
   at org.netbeans.modules.java.j2seproject.ui.customizer.CustomizerProviderImpl$StoreListener.actionPerformed(CustomizerProviderImpl.java:168)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$2$1$1.run(CustomizerDialog.java:306)
   at org.openide.filesystems.FileUtil$2.run(FileUtil.java:596)
   at org.openide.filesystems.EventControl.runAtomicAction(EventControl.java:127)
   at org.openide.filesystems.FileSystem.runAtomicAction(FileSystem.java:607)
   at org.openide.filesystems.FileUtil.runAtomicAction(FileUtil.java:580)
   at org.openide.filesystems.FileUtil.runAtomicAction(FileUtil.java:600)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$2$1.run(CustomizerDialog.java:301)
   at org.openide.util.Mutex.writeAccess(Mutex.java:397)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$2.run(CustomizerDialog.java:298)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1411)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1991)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:423)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener.actionPerformed(CustomizerDialog.java:294)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
   at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
   at java.awt.Component.processMouseEvent(Component.java:6290)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6055)
   at java.awt.Container.processEvent(Container.java:2039)
   at java.awt.Component.dispatchEventImpl(Component.java:4653)
   at java.awt.Container.dispatchEventImpl(Container.java:2097)
   at java.awt.Component.dispatchEvent(Component.java:4481)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4575)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4236)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4166)
   at java.awt.Container.dispatchEventImpl(Container.java:2083)
   at java.awt.Window.dispatchEventImpl(Window.java:2482)
   at java.awt.Component.dispatchEvent(Component.java:4481)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:648)
   at java.awt.EventQueue.access$000(EventQueue.java:84)
   at java.awt.EventQueue$1.run(EventQueue.java:607)
   at java.awt.EventQueue$1.run(EventQueue.java:605)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
   at java.awt.EventQueue$2.run(EventQueue.java:621)
   at java.awt.EventQueue$2.run(EventQueue.java:619)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:618)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:158)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)