--- old/src/java.base/share/classes/jdk/internal/module/ModulePatcher.java	2016-12-18 17:39:07.000000000 -0800
+++ new/src/java.base/share/classes/jdk/internal/module/ModulePatcher.java	2016-12-18 17:39:06.000000000 -0800
@@ -175,6 +175,12 @@
         return map.isEmpty();
     }
 
+    /*
+     * Returns the names of the patched modules.
+     */
+    Set<String> patchedModules() {
+        return map.keySet();
+    }
 
     /**
      * A ModuleReader that reads resources from a patched module.