diff -r a8dcacf95bff -r 1126f0607c70 src/hotspot/share/classfile/systemDictionary.cpp
--- a/src/hotspot/share/classfile/systemDictionary.cpp	Thu Apr 25 05:54:54 2019 -0700
+++ b/src/hotspot/share/classfile/systemDictionary.cpp	Thu Apr 25 10:56:31 2019 -0400
@@ -1824,10 +1824,10 @@
     // First, mark for unload all ClassLoaderData referencing a dead class loader.
     unloading_occurred = ClassLoaderDataGraph::do_unloading();
     if (unloading_occurred) {
-      MutexLockerEx ml2(is_concurrent ? Module_lock : NULL);
+      MutexLocker ml2(is_concurrent ? Module_lock : NULL);
       JFR_ONLY(Jfr::on_unloading_classes();)
 
-      MutexLockerEx ml1(is_concurrent ? SystemDictionary_lock : NULL);
+      MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
       ClassLoaderDataGraph::clean_module_and_package_info();
       constraints()->purge_loader_constraints();
       resolution_errors()->purge_resolution_errors();