java.lang.NullPointerException
   at org.netbeans.modules.refactoring.java.plugins.RenameTransformer.visitCompilationUnit(RenameTransformer.java:102)
   at org.netbeans.modules.refactoring.java.plugins.RenameTransformer.visitCompilationUnit(RenameTransformer.java:79)
   at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:551)
   at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:68)
   at org.netbeans.modules.refactoring.java.spi.RefactoringVisitor.scan(RefactoringVisitor.java:209)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin$TransformTask.run(JavaRefactoringPlugin.java:403)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin$TransformTask.run(JavaRefactoringPlugin.java:368)
   at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:649)
   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$UserTaskAction.run(ParserManager.java:155)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:139)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:206)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:203)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:74)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:203)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:106)
   at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:443)
   at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:414)
   at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:660)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.processFiles(JavaRefactoringPlugin.java:273)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.processFiles(JavaRefactoringPlugin.java:255)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.createAndAddElements(JavaRefactoringPlugin.java:286)
   at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.createAndAddElements(JavaRefactoringPlugin.java:302)
   at org.netbeans.modules.refactoring.java.plugins.RenameRefactoringPlugin.prepare(RenameRefactoringPlugin.java:515)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:437)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:421)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:232)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:1021)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2042)