java.util.ConcurrentModificationException: Current owner: [org.netbeans.modules.masterfs.filebasedfs.naming.NamingFactory.fromFile(NamingFactory.java:89), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObjectFactory.create(FileObjectFactory.java:456), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObjectFactory.getOrCreate(FileObjectFactory.java:419), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObjectFactory.issueIfExist(FileObjectFactory.java:391), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FileObjectFactory.getFileObject(FileObjectFactory.java:209), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.computeChildren(FolderObj.java:190), org.netbeans.modules.masterfs.filebasedfs.fileobjects.FolderObj.getChildren(FolderObj.java:156), org.openide.filesystems.FileObject.getChildren(FileObject.java:912), org.netbeans.modules.java.source.parsing.SourceFileManager.list(SourceFileManager.java:97), org.netbeans.modules.java.source.parsing.ProxyFileManager.li
   at org.netbeans.modules.java.source.parsing.ProxyFileManager.checkSingleOwnerThread(ProxyFileManager.java:529)
   at org.netbeans.modules.java.source.parsing.ProxyFileManager.list(ProxyFileManager.java:184)
   at com.sun.tools.javac.jvm.ClassReader.fillIn(ClassReader.java:2561)
   at com.sun.tools.javac.jvm.ClassReader.complete(ClassReader.java:2234)
   at com.sun.tools.javac.code.Symbol.complete(Symbol.java:422)
   at com.sun.tools.javac.comp.Enter.visitTopLevel(Enter.java:339)
   at com.sun.tools.javadoc.JavadocEnter.visitTopLevel(JavadocEnter.java:78)
   at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:457)
   at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:298)
   at com.sun.tools.javac.comp.Enter.classEnter(Enter.java:312)
   at com.sun.tools.javac.comp.Enter.complete(Enter.java:708)
   at com.sun.tools.javac.main.JavaCompiler.complete(JavaCompiler.java:979)
   at com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:945)
   at org.netbeans.modules.java.hints.spiimpl.Utilities.constructScope(Utilities.java:744)
   at org.netbeans.modules.java.hints.spiimpl.pm.PatternCompiler.compile(PatternCompiler.java:61)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.doComputeHints(HintsInvoker.java:544)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeSuggestions(HintsInvoker.java:459)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:232)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:209)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:182)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsInvoker.computeHints(HintsInvoker.java:149)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:113)
   at org.netbeans.modules.java.hints.spiimpl.hints.HintsTask.run(HintsTask.java:83)
   at org.netbeans.modules.java.source.JavaSourceAccessor$CancelableTaskWrapper.run(JavaSourceAccessor.java:298)
   at org.netbeans.modules.parsing.impl.TaskProcessor.callParserResultTask(TaskProcessor.java:561)
   at org.netbeans.modules.parsing.impl.TaskProcessor$CompilationJob.run(TaskProcessor.java:737)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
   at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
   at java.util.concurrent.FutureTask.run(FutureTask.java:166)
   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
   at java.lang.Thread.run(Thread.java:722)