java.lang.NullPointerException
        at com.sun.tools.javac.util.Name.fromString(Name.java:165)
        at com.sun.tools.javac.util.Name$Table.fromString(Name.java:553)
        at org.netbeans.modules.java.source.builder.TreeFactory.Identifier(TreeFactory.java:330)
        at org.netbeans.api.java.source.TreeMaker.Identifier(TreeMaker.java:487)
        at org.netbeans.modules.refactoring.java.CopyHandler$1.run(CopyHandler.java:94)
        at org.netbeans.modules.refactoring.java.CopyHandler$1.run(CopyHandler.java:89)
        at org.netbeans.api.java.source.JavaSource.runModificationTask(JavaSource.java:953)
        at org.netbeans.modules.refactoring.java.CopyHandler.renameFO(CopyHandler.java:115)
        at org.netbeans.modules.refactoring.java.CopyHandler.operationCopy(CopyHandler.java:135)
        at org.openide.loaders.DataLoaderPool.fireOperationEvent(DataLoaderPool.java:221)
        at org.openide.loaders.DataObject.fireOperationEvent(DataObject.java:829)
        at org.openide.loaders.DataObject.copy(DataObject.java:554)
        at org.openide.loaders.DataFolder$Paste$2.handlePaste(DataFolder.java:1628)
        at org.openide.loaders.DataTransferSupport$PasteTypeExt.doPaste(DataTransferSupport.java:176)
        at org.openide.loaders.DataTransferSupport$PasteTypeExt.paste(DataTransferSupport.java:165)
        at org.openide.actions.PasteAction$ActionPT.actionPerformed(PasteAction.java:791)
        at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:104)
        at org.openide.actions.PasteAction$ActionPT.run(PasteAction.java:815)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997)