java.lang.IllegalArgumentException: Was not listening to C:\Users\C11891A\Documents\NetBeansProjects\JavaApplication7\build\generated-sources
   at org.openide.filesystems.FileChangeImpl.removeFileChangeListenerImpl(FileChangeImpl.java:253)
   at org.openide.filesystems.FileUtil.removeFileChangeListener(FileUtil.java:311)
   at org.netbeans.modules.java.api.common.project.ui.JavaSourceNodeFactory$SourcesNodeList.removeChangeListener(JavaSourceNodeFactory.java:219)
   at org.netbeans.spi.project.ui.support.NodeFactorySupport$DelegateChildren.removeNotify(NodeFactorySupport.java:250)
   at org.openide.nodes.Children.callRemoveNotify(Children.java:580)
   at org.openide.nodes.EntrySupportDefault.finalizedChildrenArray(EntrySupportDefault.java:775)
   at org.openide.nodes.EntrySupportDefault$ChArrRef.run(EntrySupportDefault.java:867)
   at org.openide.util.lookup.implspi.ActiveQueue$Daemon.run(ActiveQueue.java:192)