java.lang.IllegalArgumentException: Child tree not found (type: 54 firstToken: 3 lastToken: 9 resource: abc/B.java) class org.netbeans.jmi.javamodel.Import$Impl abc.def.A valid:true | class org.netbeans.jmi.javamodel.Resource$Impl abc/B.java valid:true | 
	at org.netbeans.modules.javacore.jmiimpl.javamodel.MetadataElement.getASTree(MetadataElement.java:1272)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.MetadataElement.getASTree(MetadataElement.java:515)
	at org.netbeans.modules.javacore.parser.ElementInfo.getTypeAST(ElementInfo.java:86)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ImportImpl.initChildren(ImportImpl.java:225)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ImportImpl.getIdentifier(ImportImpl.java:210)
	at org.netbeans.jmi.javamodel.Import$Impl.getIdentifier(Unknown Source)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ImportImpl.setName(ImportImpl.java:94)
	at org.netbeans.jmi.javamodel.Import$Impl.setName(Unknown Source)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ImportImpl.matchElementInfo(ImportImpl.java:68)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.SemiPersistentElement.setElementInfo(SemiPersistentElement.java:140)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.SemiPersistentElement.createChildrenList(SemiPersistentElement.java:887)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.initChildren(ResourceImpl.java:337)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.initChildren(ResourceImpl.java:316)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.SemiPersistentElement.setElementInfo(SemiPersistentElement.java:146)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.updateMetadata(ResourceImpl.java:762)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.directUpdate(ResourceImpl.java:754)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.checkUpToDate(ResourceImpl.java:644)
	at org.netbeans.modules.javacore.jmiimpl.javamodel.ResourceImpl.updateFromFileObject(ResourceImpl.java:449)
	at org.netbeans.modules.javacore.ExclusiveMutex.parseIfNeeded(ExclusiveMutex.java:279)
	at org.netbeans.modules.javacore.ExclusiveMutex.enter(ExclusiveMutex.java:171)
	at org.netbeans.mdr.NBMDRepositoryImpl.beginTrans(NBMDRepositoryImpl.java:228)
	at org.netbeans.modules.javacore.internalapi.UndoManager.parseModified(UndoManager.java:485)
	at org.netbeans.modules.javacore.internalapi.UndoManager.transactionEnded(UndoManager.java:116)
	at org.netbeans.modules.javacore.internalapi.UndoManager.undo(UndoManager.java:172)
	at org.netbeans.modules.refactoring.ui.UndoAction.performAction(UndoAction.java:69)
	at org.openide.util.actions.CallableSystemAction$1.run(CallableSystemAction.java:94)
	at org.netbeans.modules.openide.util.ActionsBridge$ActionRunnable.actionPerformed(ActionsBridge.java:81)
	at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:74)
	at org.netbeans.modules.openide.actions.ActionsBridgeImpl.invokeAction(ActionsBridgeImpl.java:24)
	at org.netbeans.modules.openide.util.ActionsBridge$ActionRunnable.doRun(ActionsBridge.java:72)
	at org.netbeans.modules.openide.util.ActionsBridge$1.run(ActionsBridge.java:41)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:493)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:926)