java.util.ConcurrentModificationException
        at java.util.LinkedHashMap$LinkedHashIterator.nextEntry(LinkedHashMap.java:373)
        at java.util.LinkedHashMap$KeyIterator.next(LinkedHashMap.java:384)
        at org.netbeans.modules.versioning.VersioningManager.getLocalHistory(VersioningManager.java:304)
        at org.netbeans.modules.versioning.FilesystemInterceptor.getInterceptor(FilesystemInterceptor.java:253)
        at org.netbeans.modules.versioning.FilesystemInterceptor.fileDataCreated(FilesystemInterceptor.java:208)
        at org.netbeans.modules.versioning.FilesystemInterceptor.fileFolderCreated(FilesystemInterceptor.java:192)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEventImpl(FCLSupport.java:139)
        at org.openide.filesystems.FCLSupport$DispatchEventWrapper.dispatchEvent(FCLSupport.java:125)
        at org.openide.filesystems.FCLSupport.dispatchEvent(FCLSupport.java:102)
        at org.openide.filesystems.FileObject$ED.dispatch(FileObject.java:1109)
        at org.openide.filesystems.EventControl.invokeDispatchers(EventControl.java:205)
        at org.openide.filesystems.EventControl.exitAtomicAction(EventControl.java:179)
        at org.openide.filesystems.EventControl.runAtomicAction(EventControl.java:124)
        at org.openide.filesystems.FileSystem.runAtomicAction(FileSystem.java:539)
        at org.netbeans.modules.parsing.impl.indexing.CacheFolder.getDataFolder(CacheFolder.java:140)
        at org.netbeans.modules.parsing.impl.indexing.CacheFolder.getDataFolder(CacheFolder.java:132)
        at org.netbeans.modules.java.source.indexing.JavaIndex.getIndex(JavaIndex.java:83)
        at org.netbeans.modules.java.source.indexing.JavaIndex.getClassFolder(JavaIndex.java:106)
        at org.netbeans.modules.java.source.indexing.JavaIndex.getClassFolder(JavaIndex.java:102)
        at org.netbeans.modules.java.source.classpath.CacheClassPath.getResources(CacheClassPath.java:170)
        at org.netbeans.api.java.classpath.ClassPath.entries(ClassPath.java:295)
        at org.netbeans.modules.java.source.parsing.CachingFileManager.list(CachingFileManager.java:112)
        at org.netbeans.modules.java.source.parsing.ProxyFileManager.list(ProxyFileManager.java:174)
        at com.sun.tools.javac.jvm.ClassReader.fillIn(ClassReader.java:2168)
        at com.sun.tools.javac.jvm.ClassReader.complete(ClassReader.java:1847)
        at com.sun.tools.javac.code.Symbol.complete(Symbol.java:405)
        at com.sun.tools.javac.code.Symbol$PackageSymbol.members(Symbol.java:642)
        at com.sun.tools.javac.comp.Resolve.findType(Resolve.java:988)
        at com.sun.tools.javac.comp.Resolve.findIdent(Resolve.java:1017)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitIdentifier(Attr.java:293)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitIdentifier(Attr.java:273)
        at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:1689)
        at com.sun.source.util.SimpleTreeVisitor.visit(SimpleTreeVisitor.java:52)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:276)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:273)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1661)
        at com.sun.source.util.SimpleTreeVisitor.visit(SimpleTreeVisitor.java:52)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:276)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:273)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1661)
        at com.sun.source.util.SimpleTreeVisitor.visit(SimpleTreeVisitor.java:52)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:276)
        at com.sun.tools.javac.comp.Attr$IdentAttributer.visitMemberSelect(Attr.java:273)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1661)
        at com.sun.tools.javac.comp.Attr.attribIdent(Attr.java:269)
        at com.sun.tools.javac.main.JavaCompiler.resolveIdent(JavaCompiler.java:646)
        at com.sun.tools.javac.model.JavacElements.nameToSymbol(JavacElements.java:205)
        at com.sun.tools.javac.model.JavacElements.getTypeElement(JavacElements.java:152)
        at com.sun.tools.javac.model.JavacElements.getTypeElement(JavacElements.java:61)
        at org.netbeans.modules.vmd.midp.java.MidpJavaSupport$CheckingTask.run(MidpJavaSupport.java:297)
        at org.netbeans.modules.vmd.midp.java.MidpJavaSupport$CheckingTask.run(MidpJavaSupport.java:290)
        at org.netbeans.api.java.source.JavaSource$MimeTask.run(JavaSource.java:533)
        at org.netbeans.modules.parsing.api.ParserManager$MimeTaskAction.run(ParserManager.java:335)
        at org.netbeans.modules.parsing.api.ParserManager$MimeTaskAction.run(ParserManager.java:319)
        at org.netbeans.modules.parsing.impl.TaskProcessor.runUserTask(TaskProcessor.java:190)
        at org.netbeans.modules.parsing.api.ParserManager.parse(ParserManager.java:307)
        at org.netbeans.api.java.source.JavaSource.runUserActionTaskImpl(JavaSource.java:400)
        at org.netbeans.api.java.source.JavaSource.runUserActionTask(JavaSource.java:392)
        at org.netbeans.modules.vmd.midp.java.MidpJavaSupport.checkValidity(MidpJavaSupport.java:257)
        at org.netbeans.modules.vmd.midp.java.MidpJavaSupport.checkValidity(MidpJavaSupport.java:232)
        at org.netbeans.modules.vmd.midp.producers.MidpComponentProducer.checkValidity(MidpComponentProducer.java:69)
        at org.netbeans.modules.vmd.palette.PaletteKit.checkValidityCore(PaletteKit.java:390)
        at org.netbeans.modules.vmd.palette.PaletteKit.run(PaletteKit.java:343)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:602)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1084)