--- old/src/share/vm/gc/shared/genOopClosures.inline.hpp	2015-10-16 17:28:12.000000000 +0200
+++ new/src/share/vm/gc/shared/genOopClosures.inline.hpp	2015-10-16 17:28:12.000000000 +0200
@@ -34,11 +34,12 @@
 #include "gc/shared/space.hpp"
 
 inline OopsInGenClosure::OopsInGenClosure(Generation* gen) :
-  ExtendedOopClosure(gen->ref_processor()), _orig_gen(gen), _rs(NULL) {
+  ExtendedOopClosure(gen->ref_processor()), _gen(NULL), _rs(NULL) {
   set_generation(gen);
 }
 
 inline void OopsInGenClosure::set_generation(Generation* gen) {
+  assert(_gen == NULL, "Generation already initialized");
   _gen = gen;
   _gen_boundary = _gen->reserved().start();
   // Barrier set for the heap, must be set after heap is initialized
@@ -48,6 +49,10 @@
   }
 }
 
+inline void OopsInGenClosure::assert_generation(Generation* gen) {
+  assert(_gen == gen, "Generations mismatch. Fix it now!!");
+}
+
 template <class T> inline void OopsInGenClosure::do_barrier(T* p) {
   assert(generation()->is_in_reserved(p), "expected ref in generation");
   T heap_oop = oopDesc::load_heap_oop(p);