--- old/src/share/vm/oops/arrayKlass.hpp	2011-12-07 12:03:23.000000000 +0100
+++ new/src/share/vm/oops/arrayKlass.hpp	2011-12-07 12:03:23.000000000 +0100
@@ -73,7 +73,7 @@
   oop* adr_component_mirror()           { return (oop*)&this->_component_mirror;}
 
   // Compiler/Interpreter offset
-  static ByteSize component_mirror_offset() { return byte_offset_of(arrayKlass, _component_mirror); }
+  static ByteSize component_mirror_offset() { return in_ByteSize(sizeof(klassOopDesc)) + byte_offset_of(arrayKlass, _component_mirror); }
 
   virtual klassOop java_super() const;//{ return SystemDictionary::Object_klass(); }