java.lang.NullPointerException
   at org.netbeans.lib.profiler.heap.NearestGCRoot.fillZeroLevel(NearestGCRoot.java:257)
   at org.netbeans.lib.profiler.heap.NearestGCRoot.computeGCRoots(NearestGCRoot.java:128)
   at org.netbeans.lib.profiler.heap.NearestGCRoot.getNearestGCRootPointer(NearestGCRoot.java:98)
   at org.netbeans.lib.profiler.heap.HprofHeap.getNearestGCRootPointer(HprofHeap.java:679)
   at org.netbeans.lib.profiler.heap.InstanceDump.getNearestGCRootPointer(InstanceDump.java:108)
   at org.netbeans.modules.profiler.heapwalk.model.BrowserUtils.computeChildrenToNearestGCRoot(BrowserUtils.java:233)
   at org.netbeans.modules.profiler.heapwalk.ReferencesBrowserController$2.doInBackground(ReferencesBrowserController.java:240)
   at org.netbeans.lib.profiler.ui.SwingWorker$2.run(SwingWorker.java:159)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)