java.lang.AssertionError
        at org.netbeans.modules.java.source.parsing.JavacParser.getResult(JavacParser.java:339)
        at org.netbeans.modules.java.source.parsing.JavacParser.getResult(JavacParser.java:148)
        at org.netbeans.modules.parsing.api.ResultIterator.getParserResult(ResultIterator.java:126)
        at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:642)
        at org.netbeans.modules.parsing.api.ParserManager$MultiUserTaskAction.run(ParserManager.java:164)
        at org.netbeans.modules.parsing.api.ParserManager$MultiUserTaskAction.run(ParserManager.java:136)
        at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:188)
        at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:100)
        at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:663)
        at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.processFiles(JavaRefactoringPlugin.java:244)
        at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.createAndAddElements(JavaRefactoringPlugin.java:254)
        at org.netbeans.modules.refactoring.java.spi.JavaRefactoringPlugin.createAndAddElements(JavaRefactoringPlugin.java:270)
        at org.netbeans.modules.refactoring.java.plugins.ChangeParametersPlugin.prepare(ChangeParametersPlugin.java:193)
        at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare2(AbstractRefactoring.java:419)
        at org.netbeans.modules.refactoring.api.AbstractRefactoring.pluginsPrepare(AbstractRefactoring.java:403)
        at org.netbeans.modules.refactoring.api.AbstractRefactoring.prepare(AbstractRefactoring.java:214)
        at org.netbeans.modules.refactoring.spi.impl.ParametersPanel$Prepare.run(ParametersPanel.java:787)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:573)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1005)