java.lang.ClassCastException: org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObj cannot be cast to org.openide.loaders.DataObject
   at org.netbeans.modules.refactoring.spi.impl.UndoableWrapper$UndoableEditDelegate.<init>(UndoableWrapper.java:116)
   at org.netbeans.modules.refactoring.spi.impl.UndoableWrapper$UndoableEditDelegate.<init>(UndoableWrapper.java:106)
   at org.netbeans.modules.refactoring.spi.impl.UndoableWrapper.wrap(UndoableWrapper.java:85)
   at org.netbeans.editor.BaseDocument.fireUndoableEditUpdate(BaseDocument.java:1636)
   at org.netbeans.editor.BaseDocument.checkAndFireAtomicEdits(BaseDocument.java:2103)
   at org.netbeans.editor.BaseDocument.atomicUnlockImpl(BaseDocument.java:1765)
   at org.netbeans.editor.BaseDocument.atomicUnlockImpl(BaseDocument.java:1752)
   at org.netbeans.editor.BaseDocument.runAtomicAsUser(BaseDocument.java:1424)
   at org.netbeans.editor.BaseDocument.runAtomic(BaseDocument.java:1405)
   at org.netbeans.modules.java.source.save.CasualDiff.diff(CasualDiff.java:275)
   at org.netbeans.api.java.source.WorkingCopy.processCurrentCompilationUnit(WorkingCopy.java:731)
   at org.netbeans.api.java.source.WorkingCopy.getChanges(WorkingCopy.java:897)
   at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:652)
   at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:639)
   at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:493)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:593)
   at org.netbeans.modules.parsing.api.ParserManager$MultiUserTaskAction.run(ParserManager.java:191)
   at org.netbeans.modules.parsing.api.ParserManager$MultiUserTaskAction.run(ParserManager.java:163)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:206)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:203)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:74)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:203)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:108)
   at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:443)
   at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:414)
   at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:660)
   at org.netbeans.modules.java.hints.spiimpl.batch.BatchUtilities.applyFixes(BatchUtilities.java:383)
   at org.netbeans.modules.java.hints.spiimpl.refactoring.AbstractApplyHintsRefactoringPlugin$DelegatingTransaction.commit(AbstractApplyHintsRefactoringPlugin.java:432)
   at org.netbeans.modules.refactoring.api.RefactoringSession.reallyDoRefactoring(RefactoringSession.java:166)
   at org.netbeans.modules.refactoring.api.RefactoringSession.access$100(RefactoringSession.java:79)
   at org.netbeans.modules.refactoring.api.RefactoringSession$1.run(RefactoringSession.java:122)
   at org.netbeans.modules.refactoring.api.RefactoringSession$1.run(RefactoringSession.java:120)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks.runWithOnSaveTasksDisabled(BeforeSaveTasks.java:93)
   at org.netbeans.editor.Utilities.runWithOnSaveTasksDisabled(Utilities.java:1621)
   at org.netbeans.modules.refactoring.api.RefactoringSession.doRefactoring(RefactoringSession.java:120)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringPanel$2.run(RefactoringPanel.java:555)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2042)