diff -r 33a76b934213 -r 8624981f1ffa src/hotspot/share/oops/klass.hpp
--- a/src/hotspot/share/oops/klass.hpp	Thu May 03 08:07:20 2018 -0400
+++ b/src/hotspot/share/oops/klass.hpp	Fri Apr 27 15:00:04 2018 -0400
@@ -638,9 +638,9 @@
   // Klass is considered alive.  Has already been marked as unloading.
   bool is_loader_alive() const { return !class_loader_data()->is_unloading(); }
 
-  static void clean_weak_klass_links(bool clean_alive_klasses = true);
+  static void clean_weak_klass_links(bool unloading_occurred, bool clean_alive_klasses = true);
   static void clean_subklass_tree() {
-    clean_weak_klass_links(false /* clean_alive_klasses */);
+    clean_weak_klass_links(/*unloading_occurred*/ true , /* clean_alive_klasses */ false);
   }
 
   // GC specific object visitors