GWT com.google.gwt.json.client.* JSON classes not supporting for jsinterop?

Question

When I try to compile and run the code

JSONValue jv = JSONParser.parseStrict(jsonString);

I got console message as following-

[WARN] Some stale types ([com.mycompany.gwtjs.client.AjaxForm$1, com.mycompany.gwtjs.client.AjaxForm$1$1, com.mycompany.gwtjs.client.AjaxForm]) were not reprocessed as was expected. This is either a compiler bug or a Generator has legitimately stopped creating these types.

The link http://www.gwtproject.org/javadoc/latest/index.html has package which is having the classes i used.

Please anyone has having idea to solve this?

Thanks.