java.lang.ClassNotFoundException: org.openide.util.Enumerations$RNulls
   at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
   at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
   at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Caused: java.lang.NoClassDefFoundError: org/openide/util/Enumerations$RNulls
   at org.openide.util.Enumerations.removeNulls(Enumerations.java:161)
   at org.openide.filesystems.AbstractFileSystem.existingFileObjects(AbstractFileSystem.java:410)
   at org.openide.filesystems.AbstractFileSystem.existingFileObjects(AbstractFileSystem.java:385)
   at org.openide.filesystems.JarFileSystem.refreshExistingFileObjects(JarFileSystem.java:799)
   at org.openide.filesystems.JarFileSystem.parse(JarFileSystem.java:887)
   at org.openide.filesystems.JarFileSystem.access$100(JarFileSystem.java:93)
   at org.openide.filesystems.JarFileSystem$1.fileChanged(JarFileSystem.java:356)
   at sun.reflect.GeneratedMethodAccessor7.invoke(GeneratedMethodAccessor7.java:0)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:597)
   at org.openide.util.WeakListenerImpl$ProxyListener.invoke(WeakListenerImpl.java:457)
   at $Proxy1.fileChanged(.java:0)
   at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEventImpl(FCLSupport.java:145)
   at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEvent(FCLSupport.java:128)
   at org.openide.filesystems.FCLSupport.dispatchEvent(FCLSupport.java:105)
   at org.openide.filesystems.FileObject$ED.dispatch(FileObject.java:1313)
   at org.openide.filesystems.FileSystem$EventDispatcher.run(FileSystem.java:997)
   at org.openide.filesystems.EventControl.dispatchEvent(EventControl.java:84)
   at org.openide.filesystems.FileSystem.dispatchEvent(FileSystem.java:642)
   at org.openide.filesystems.FileObject.dispatchEvent(FileObject.java:635)
   at org.openide.filesystems.FileObject.fireFileChangedEvent(FileObject.java:603)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.fireFileChangedEvent(BaseFileObj.java:681)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObj.refreshImpl(FileObj.java:319)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.refresh(BaseFileObj.java:827)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObj.refresh(FileObj.java:330)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.refreshImpl(FolderObj.java:476)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.BaseFileObj.refresh(BaseFileObj.java:827)
   at org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.refresh(FolderObj.java:554)
   at org.openide.filesystems.FileObject.refresh(FileObject.java:1201)
   at org.netbeans.modules.masterfs.watcher.Watcher$1.run(Watcher.java:380)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1454)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2036)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.NoClassDefFoundError: org/openide/util/Enumerations$RNulls
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1495)
   at org.netbeans.modules.masterfs.watcher.Watcher.enqueue(Watcher.java:393)
   at org.netbeans.modules.masterfs.watcher.Watcher.access$200(Watcher.java:74)
   at org.netbeans.modules.masterfs.watcher.Watcher$Ext.run(Watcher.java:327)
   at java.lang.Thread.run(Thread.java:662)