--- old/src/hotspot/share/gc/z/zHeap.cpp	2019-11-21 14:24:41.194739232 +0100
+++ new/src/hotspot/share/gc/z/zHeap.cpp	2019-11-21 14:24:40.990735911 +0100
@@ -352,12 +352,12 @@
   ZRendezvousClosure cl;
   Handshake::execute(&cl);
 
-  // Purge stale metadata and nmethods that were unlinked
-  _unload.purge();
-
   // Unblock resurrection of weak/phantom references
   ZResurrection::unblock();
 
+  // Purge stale metadata and nmethods that were unlinked
+  _unload.purge();
+
   // Enqueue Soft/Weak/Final/PhantomReferences. Note that this
   // must be done after unblocking resurrection. Otherwise the
   // Finalizer thread could call Reference.get() on the Finalizers