java.lang.NoClassDefFoundError: Could not initialize class org.netbeans.modules.project.ant.AntBasedProjectFactorySingleton
   at org.netbeans.modules.project.ant.ProjectLibraryProvider.getOpenAreas(ProjectLibraryProvider.java:184)
   at org.netbeans.modules.project.libraries.LibraryAccessor.getOpenAreas(LibraryAccessor.java:100)
   at org.netbeans.api.project.libraries.LibraryManager.getOpenManagers(LibraryManager.java:495)
   at org.netbeans.modules.java.j2seplatform.libraries.J2SELibraryClassPathProvider.findClassPath(J2SELibraryClassPathProvider.java:74)
   at org.netbeans.api.java.classpath.ClassPath.getClassPath(ClassPath.java:632)
   at org.netbeans.modules.parsing.impl.indexing.errors.Utilities.getSourceClassPathFor(Utilities.java:66)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.computePersistentFile(TaskCache.java:429)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.getErrors(TaskCache.java:135)
   at org.netbeans.modules.parsing.impl.indexing.errors.TaskCache.isInError(TaskCache.java:354)
   at org.netbeans.modules.parsing.impl.indexing.errors.ErrorAnnotator$1.run(ErrorAnnotator.java:307)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1411)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1991)