java.util.ConcurrentModificationException
   at java.util.Hashtable$Enumerator.next(Hashtable.java:1031)
   at org.openide.util.NbCollections.checkedMapByCopy(NbCollections.java:151)
   at org.netbeans.spi.project.support.ant.ProjectProperties.getStockPropertyPreprovider(ProjectProperties.java:426)
   at org.netbeans.spi.project.support.ant.AntProjectHelper.getStockPropertyPreprovider(AntProjectHelper.java:1202)
   at org.netbeans.modules.java.j2seproject.J2SEProject.createEvaluator(J2SEProject.java:250)
   at org.netbeans.modules.java.j2seproject.J2SEProject.<init>(J2SEProject.java:195)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance0(NativeConstructorAccessorImpl.java:0)
   at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
   at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
   at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
   at org.netbeans.modules.project.ant.AntBasedGenericType.createProject(AntBasedGenericType.java:129)
   at org.netbeans.modules.project.ant.AntBasedProjectFactorySingleton.loadProject(AntBasedProjectFactorySingleton.java:256)
   at org.netbeans.api.project.ProjectManager.createProject(ProjectManager.java:365)
   at org.netbeans.api.project.ProjectManager.access$300(ProjectManager.java:85)
   at org.netbeans.api.project.ProjectManager$2.run(ProjectManager.java:286)
   at org.netbeans.api.project.ProjectManager$2.run(ProjectManager.java:233)
   at org.openide.util.Mutex.readAccess(Mutex.java:330)
   at org.netbeans.api.project.ProjectManager.findProject(ProjectManager.java:233)
   at org.netbeans.modules.projectapi.SimpleFileOwnerQueryImplementation.getOwner(SimpleFileOwnerQueryImplementation.java:131)
   at org.netbeans.modules.projectapi.SimpleFileOwnerQueryImplementation.getOwner(SimpleFileOwnerQueryImplementation.java:97)
   at org.netbeans.api.project.FileOwnerQuery.getOwner(FileOwnerQuery.java:150)
   at org.netbeans.modules.projectapi.ProjectSharabilityQuery.getSharability(ProjectSharabilityQuery.java:63)
   at org.netbeans.api.queries.SharabilityQuery.getSharability(SharabilityQuery.java:113)
   at org.netbeans.modules.mercurial.util.HgUtils.isIgnored(HgUtils.java:442)
   at org.netbeans.modules.mercurial.FileStatusCache$1.run(FileStatusCache.java:118)
   at org.netbeans.modules.mercurial.FileStatusCache.handleIgnoredFiles(FileStatusCache.java:137)
   at org.netbeans.modules.mercurial.FileStatusCache.checkForIgnoredFile(FileStatusCache.java:153)
   at org.netbeans.modules.mercurial.FileStatusCache.getCachedStatus(FileStatusCache.java:295)
   at org.netbeans.modules.mercurial.FileStatusCache.getCachedStatus(FileStatusCache.java:276)
   at org.netbeans.modules.mercurial.MercurialAnnotator.annotateName(MercurialAnnotator.java:175)
   at org.netbeans.modules.versioning.VersioningAnnotationProvider$Cache.annotate(VersioningAnnotationProvider.java:620)
   at org.netbeans.modules.versioning.VersioningAnnotationProvider$Cache.annotate(VersioningAnnotationProvider.java:653)
   at org.netbeans.modules.versioning.VersioningAnnotationProvider$Cache.access$2000(VersioningAnnotationProvider.java:466)
   at org.netbeans.modules.versioning.VersioningAnnotationProvider$Cache$AnnotationRefreshTask.run(VersioningAnnotationProvider.java:730)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)
Caused: org.openide.util.RequestProcessor$FastItem: task failed due to: java.util.ConcurrentModificationException