--- a/src/hotspot/share/services/heapDumper.cpp	Mon Aug 19 12:40:27 2019 +0200
+++ b/src/hotspot/share/services/heapDumper.cpp	Tue Jul 02 12:28:41 2019 +0200
@@ -760,7 +760,7 @@
   switch (type) {
     case JVM_SIGNATURE_CLASS :
     case JVM_SIGNATURE_ARRAY : {
-      oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF>(offset);
+      oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
       assert(oopDesc::is_oop_or_null(o), "Expected an oop or NULL at " PTR_FORMAT, p2i(o));
       writer->write_objectID(o);
       break;