--- a/hotspot/src/share/vm/runtime/arguments.cpp	Tue May 08 11:29:21 2012 -0700
+++ b/hotspot/src/share/vm/runtime/arguments.cpp	Mon May 21 14:56:33 2012 -0700
@@ -829,6 +829,9 @@
     } else {
       jio_fprintf(defaultStream::error_stream(), "%s", locked_message_buf);
     }
+  } else {
+    jio_fprintf(defaultStream::error_stream(),
+                "Unrecognized VM option '%s'\n", argname);
   }
 
   // allow for commandline "commenting out" options like -XX:#+Verbose