--- old/src/share/vm/memory/iterator.cpp	2014-06-12 10:42:43.746104102 +0200
+++ new/src/share/vm/memory/iterator.cpp	2014-06-12 10:42:43.630104106 +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);
 }