--- old/src/share/vm/gc/g1/heapRegion.inline.hpp	2015-06-06 02:21:45.000000000 +0200
+++ new/src/share/vm/gc/g1/heapRegion.inline.hpp	2015-06-06 02:21:45.000000000 +0200
@@ -95,7 +95,7 @@
 inline bool
 HeapRegion::block_is_obj(const HeapWord* p) const {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
-  if (ClassUnloadingWithConcurrentMark) {
+  if (ClassUnloading && ClassUnloadingWithConcurrentMark) {
     return !g1h->is_obj_dead(oop(p), this);
   }
   return p < top();
@@ -111,7 +111,7 @@
     return oop(addr)->size();
   }
 
-  assert(ClassUnloadingWithConcurrentMark,
+  assert(ClassUnloading && ClassUnloadingWithConcurrentMark,
       err_msg("All blocks should be objects if G1 Class Unloading isn't used. "
               "HR: ["PTR_FORMAT", "PTR_FORMAT", "PTR_FORMAT") "
               "addr: " PTR_FORMAT,