java.lang.NullPointerException
   at org.netbeans.api.java.source.ElementUtilities.enclosingTypeElementImpl(ElementUtilities.java:146)
   at org.netbeans.api.java.source.ElementUtilities.enclosingTypeElement(ElementUtilities.java:141)
   at org.netbeans.modules.refactoring.java.RefactoringUtils.getOverridenMethods(RefactoringUtils.java:104)
   at org.netbeans.modules.refactoring.java.api.JavaRefactoringUtils.getOverriddenMethods(JavaRefactoringUtils.java:68)
   at org.netbeans.modules.refactoring.java.plugins.OverriddenAbsMethodFinder.run(OverriddenAbsMethodFinder.java:65)
   at org.netbeans.modules.refactoring.java.plugins.OverriddenAbsMethodFinder.run(OverriddenAbsMethodFinder.java:47)
   at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:488)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:583)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:150)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:134)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:200)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:197)
   at org.netbeans.modules.masterfs.filebasedfs.utils.FileChangedManager.priorityIO(FileChangedManager.java:176)
   at org.netbeans.modules.masterfs.providers.ProvidedExtensions.priorityIO(ProvidedExtensions.java:360)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:72)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:197)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:102)
   at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:438)
   at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:409)
   at org.netbeans.modules.refactoring.java.plugins.SafeDeleteRefactoringPlugin.prepare(SafeDeleteRefactoringPlugin.java:128)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:427)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:411)
   at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:222)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:1012)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)