diff -r 46eac084082d -r 75e4ce0fa1ba src/hotspot/share/gc/z/zCollectedHeap.hpp
--- a/src/hotspot/share/gc/z/zCollectedHeap.hpp	Thu Sep 20 14:04:43 2018 +0200
+++ b/src/hotspot/share/gc/z/zCollectedHeap.hpp	Thu Sep 20 14:04:44 2018 +0200
@@ -56,9 +56,6 @@
 public:
   static ZCollectedHeap* heap();
 
-  using CollectedHeap::ensure_parsability;
-  using CollectedHeap::resize_all_tlabs;
-
   ZCollectedHeap(ZCollectorPolicy* policy);
   virtual Name kind() const;
   virtual const char* name() const;
@@ -78,6 +75,8 @@
   virtual bool is_in(const void* p) const;
   virtual bool is_in_closed_subset(const void* p) const;
 
+  virtual void fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap);
+
   virtual HeapWord* mem_allocate(size_t size, bool* gc_overhead_limit_was_exceeded);
   virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
                                                        size_t size,