java.lang.NoClassDefFoundError: Could not initialize class org.netbeans.modules.masterfs.filebasedfs.FileBasedFileSystem
   at org.netbeans.modules.masterfs.filebasedfs.FileBasedURLMapper.getFileObjects(FileBasedURLMapper.java:131)
   at org.netbeans.modules.masterfs.MasterURLMapper.getFileObjects(MasterURLMapper.java:62)
   at org.openide.filesystems.URLMapper.findFileObject(URLMapper.java:213)
   at org.openide.filesystems.FileUtil.toFileObject(FileUtil.java:980)
   at org.openide.filesystems.FileUtil.getDiskFileSystemFor(FileUtil.java:131)
   at org.openide.filesystems.FileUtil.refreshFor(FileUtil.java:151)
   at org.openide.filesystems.FileUtil$1.run(FileUtil.java:177)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:641)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1123)