--- old/src/share/vm/utilities/workgroup.hpp	Thu Mar 10 19:21:24 2011
+++ new/src/share/vm/utilities/workgroup.hpp	Thu Mar 10 19:21:24 2011
@@ -36,6 +36,20 @@
 # include "thread_windows.inline.hpp"
 #endif
 
+// Task class hierarchy:
+//   AbstractGangTask
+//     AbstractGangTaskWOopQueues
+//
+// Gang/Group class hierarchy:
+//   AbstractWorkGang
+//     WorkGang
+//       FlexibleWorkGang
+//         YieldingFlexibleWorkGang (defined in another file)
+//
+// Worker class hierarchy:
+//   GangWorker (subclass of WorkerThread)
+//     YieldingFlexibleGangWorker   (defined in another file)
+
 // Forward declarations of classes defined here
 
 class WorkGang;