code: public Result xml(Object obj) {
          Result response = ok();
          holder.setControllerResult(response);
          response.contentType(MediaType.APPLICATION_XML).renderable(obj);
          return response;
      }
docs: This method will send a XML response to the client.
  It will not use any layouts.
  Use it to build app.services.
  
  @param obj
  @return {@link Result}, to accept additional information. The response is automatically
  has its content type set to "application/xml"