diff -r 4a2ed49abd51 -r ecd24264898b src/share/vm/oops/instanceKlass.hpp
--- a/src/share/vm/oops/instanceKlass.hpp	Fri Dec 07 10:55:16 2012 -0800
+++ b/src/share/vm/oops/instanceKlass.hpp	Tue Jan 08 14:04:25 2013 -0500
@@ -31,6 +31,7 @@
 #include "oops/fieldInfo.hpp"
 #include "oops/instanceOop.hpp"
 #include "oops/klassVtable.hpp"
+#include "runtime/atomic.hpp"
 #include "runtime/handles.hpp"
 #include "runtime/os.hpp"
 #include "utilities/accessFlags.hpp"
@@ -170,6 +171,11 @@
     initialization_error                // error happened during initialization
   };
 
+  static int number_of_instance_classes() { return _total_instanceKlass_count; }
+
+ private:
+  static volatile int _total_instanceKlass_count;
+
  protected:
   // Protection domain.
   oop             _protection_domain;