--- old/src/share/vm/prims/whitebox.cpp	2015-11-05 09:34:52.919131949 +0100
+++ new/src/share/vm/prims/whitebox.cpp	2015-11-05 09:34:52.837129528 +0100
@@ -322,8 +322,8 @@
 WB_END
 
 WB_ENTRY(jboolean, WB_G1InConcurrentMark(JNIEnv* env, jobject o))
-  G1CollectedHeap* g1 = G1CollectedHeap::heap();
-  return g1->concurrent_mark()->cmThread()->during_cycle();
+  G1CollectedHeap* g1h = G1CollectedHeap::heap();
+  return g1h->concurrent_mark()->cmThread()->during_cycle();
 WB_END
 
 WB_ENTRY(jboolean, WB_G1StartMarkCycle(JNIEnv* env, jobject o))