--- old/src/hotspot/share/gc/shared/memAllocator.cpp	2019-11-22 13:54:11.716105155 +0100
+++ new/src/hotspot/share/gc/shared/memAllocator.cpp	2019-11-22 13:54:11.472101030 +0100
@@ -401,6 +401,12 @@
   return finish(mem);
 }
 
+oop ObjBufferAllocator::initialize(HeapWord* mem) const {
+  oopDesc::set_klass_gap(mem, 0);
+  return finish(mem);
+}
+
+
 MemRegion ObjArrayAllocator::obj_memory_range(oop obj) const {
   if (_do_zero) {
     return MemAllocator::obj_memory_range(obj);