--- old/src/hotspot/share/gc/shared/memAllocator.hpp	2019-08-07 12:22:08.130842371 +0200
+++ new/src/hotspot/share/gc/shared/memAllocator.hpp	2019-08-07 12:22:07.887834449 +0200
@@ -59,7 +59,7 @@
   // This finish constructing an oop by installing the mark word and the Klass* pointer
   // last. At the point when the Klass pointer is initialized, this is a constructed object
   // that must be parseable as an oop by concurrent collectors.
-  oop finish(HeapWord* mem) const;
+  virtual oop finish(HeapWord* mem) const;
 
   // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
   // allocation. A GC implementation may override this function to satisfy the allocation