java.lang.ClassCastException: com.sun.tools.javac.tree.JCTree$JCVariableDecl cannot be cast to com.sun.source.tree.MethodTree
   at org.netbeans.modules.java.editor.codegen.GeneratorUtils.checkDuplicates(GeneratorUtils.java:445)
   at org.netbeans.modules.java.editor.codegen.GeneratorUtils.insertClassMembers(GeneratorUtils.java:202)
   at org.netbeans.modules.java.editor.codegen.GeneratorUtils.insertClassMember(GeneratorUtils.java:252)
   at org.netbeans.modules.java.hints.introduce.IntroduceHint$InsertClassMember.insertClassMember(IntroduceHint.java:966)
   at org.netbeans.modules.java.hints.introduce.IntroduceHint.insertField(IntroduceHint.java:755)
   at org.netbeans.modules.java.hints.introduce.IntroduceFieldFix$Worker.run(IntroduceFieldFix.java:365)
   at org.netbeans.modules.java.hints.introduce.IntroduceFieldFix$Worker.run(IntroduceFieldFix.java:179)
   at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:635)
   at org.netbeans.api.java.source.JavaSource$1.run(JavaSource.java:625)
   at org.netbeans.api.java.source.JavaSource$MultiTask.run(JavaSource.java:479)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callUserTask(TaskProcessor.java:609)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:153)
   at org.netbeans.modules.parsing.api.ParserManager$UserTaskAction.run(ParserManager.java:137)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:204)
   at org.netbeans.modules.parsing.impl.TaskProcessor$2.call(TaskProcessor.java:201)
   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.nb.DataObjectEnvFactory.runPriorityIO(DataObjectEnvFactory.java:141)
   at org.netbeans.modules.parsing.impl.Utilities.runPriorityIO(Utilities.java:88)
   at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:201)
   at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:104)
   at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:429)
   at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:400)
   at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:646)
   at org.netbeans.modules.java.hints.introduce.IntroduceFieldFix.implement(IntroduceFieldFix.java:170)
   at org.netbeans.modules.editor.hints.HintsUI$1.run(HintsUI.java:837)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)