java.lang.NullPointerException
        at org.netbeans.modules.refactoring.java.ui.ChangeParametersPanel$1.run(ChangeParametersPanel.java:130)
        at org.netbeans.modules.refactoring.java.ui.ChangeParametersPanel$1.run(ChangeParametersPanel.java:125)
        at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:450)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:129)
        at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:113)
        at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:189)
        at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:99)
        at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:405)
        at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:376)
        at org.netbeans.modules.refactoring.java.ui.ChangeParametersPanel.initialize(ChangeParametersPanel.java:125)
        at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$10.run(ParametersPanel.java:500)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:573)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1005)