--- old/src/java.base/share/classes/jdk/internal/module/ServicesCatalog.java	2020-07-22 12:00:43.628254247 -0700
+++ new/src/java.base/share/classes/jdk/internal/module/ServicesCatalog.java	2020-07-22 12:00:43.448247472 -0700
@@ -171,6 +171,13 @@
         return catalog;
     }
 
+    static void setServicesCatalog(ClassLoader loader, ServicesCatalog catalog) {
+        ServicesCatalog previous = CLV.putIfAbsent(loader, catalog);
+        if (previous != null) {
+            throw new RuntimeException("unexpected: " + previous);
+        }
+    }
+
     // the ServicesCatalog registered to a class loader
     private static final ClassLoaderValue<ServicesCatalog> CLV = new ClassLoaderValue<>();
 }