diff -r 90d417fd526c -r 41be00d23622 samples/counters.js
--- a/samples/counters.js	Wed May 07 21:33:30 2014 -0700
+++ b/samples/counters.js	Wed May 07 20:20:58 2014 +0530
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -33,7 +33,11 @@
  * This file can be run along with any script you want to run
  * to print aggregate stat counters from nashorn.
  *
- * Usage:  jjs <your-file.js> counters.js
+ * Usage:  jjs -J-Dnashorn.debug <your-file.js> counters.js
  */
 
-Debug.dumpCounters();
+if (java.lang.System.getProperty("nashorn.debug") == null) {
+    print("Usage: jjs -J-Dnashorn.debug <your-file.js> counters.js");
+} else {
+    Debug.dumpCounters();
+}