--- a/src/hotspot/share/gc/z/zRootsIterator.hpp	Tue Nov 20 10:50:54 2018 +0530
+++ b/src/hotspot/share/gc/z/zRootsIterator.hpp	Tue Nov 20 08:17:24 2018 +0100
@@ -124,7 +124,7 @@
   ZParallelOopsDo<ZConcurrentRootsIterator, &ZConcurrentRootsIterator::do_class_loader_data_graph> _class_loader_data_graph;
 
 public:
-  ZConcurrentRootsIterator(bool marking);
+  ZConcurrentRootsIterator(bool marking = false);
   ~ZConcurrentRootsIterator();
 
   void oops_do(ZRootsIteratorClosure* cl);