--- a/hotspot/src/share/vm/memory/iterator.cpp	Tue Jun 24 15:50:50 2014 +0200
+++ b/hotspot/src/share/vm/memory/iterator.cpp	Tue Jun 24 16:20:15 2014 +0200
@@ -27,6 +27,7 @@
 #include "oops/oop.inline.hpp"
 
 void KlassToOopClosure::do_klass(Klass* k) {
+  assert(_oop_closure != NULL, "Not initialized?");
   k->oops_do(_oop_closure);
 }