--- old/src/share/vm/gc/g1/g1OopClosures.hpp	2017-05-05 14:06:36.879404383 +0200
+++ new/src/share/vm/gc/g1/g1OopClosures.hpp	2017-05-05 14:06:36.777401361 +0200
@@ -199,7 +199,7 @@
   G1UpdateRSOrPushRefOopClosure(G1CollectedHeap* g1h,
                                 G1ParPushHeapRSClosure* push_ref_cl,
                                 bool record_refs_into_cset,
-                                uint worker_i = 0);
+                                uint worker_i);
 
   void set_from(HeapRegion* from) {
     assert(from != NULL, "from region must be non-NULL");