java.lang.NullPointerException
   at com.sun.tools.javac.api.JavacTrees.getElement(JavacTrees.java:228)
   at org.netbeans.modules.refactoring.java.api.MemberInfo.create(MemberInfo.java:165)
   at org.netbeans.modules.refactoring.java.ui.EncapsulateFieldPanel.initialize(EncapsulateFieldPanel.java:193)
   at org.netbeans.modules.refactoring.java.ui.EncapsulateFieldPanel$1.run(EncapsulateFieldPanel.java:174)
   at org.netbeans.modules.refactoring.java.ui.EncapsulateFieldPanel$1.run(EncapsulateFieldPanel.java:169)
   at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:488)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:586)
   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:201)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:198)
   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:198)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:106)
   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.ui.EncapsulateFieldPanel.initialize(EncapsulateFieldPanel.java:169)
   at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$11.run(ParametersPanel.java:636)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1432)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2044)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to: java.lang.NullPointerException