JsonpRequestBuilder and inherits?

Hi, all, When I tried to gwt compile my code, I got: Line 33: No source code is available for type com.google.gwt.jsonp.client.JsonpRequestBuilder; did you forget to inherit a required module? Do I need to add a line to the gwt.xml file? If so, what would that be? Cheers -- You received this

Use of com.google.gwt.jsonp.client.JsonpRequestBuilde and compiler error message

Hi, all, I have tried to use the said class in my GWT project. When I tried to compile the code, I got this error message: No source code is available for type com.google.gwt.jsonp.client.JsonpRequestBuilder; did you forget to inherit a required module? It is not obvious from the doc if I need