--- old/src/hotspot/share/memory/heapShared.cpp	2018-10-21 22:34:17.120872850 -0700
+++ new/src/hotspot/share/memory/heapShared.cpp	2018-10-21 22:34:16.848862472 -0700
@@ -417,6 +417,11 @@
         Klass* resolved_k = SystemDictionary::resolve_or_null(
                                               (obj_k)->name(), THREAD);
         if (resolved_k != obj_k) {
+          assert(!SystemDictionary::is_well_known_klass(resolved_k),
+                 "shared well-known classes must not be replaced by JVMTI ClassFileLoadHook");
+          ResourceMark rm;
+          log_info(cds, heap)("Failed to load subgraph because %s was not loaded from archive",
+                              resolved_k->external_name());
           return;
         }
         if ((obj_k)->is_instance_klass()) {