code: private void createDefaultResponse(Route route, String controllerLayout) throws InstantiationException, IllegalAccessException {
             String controllerPath = Router.getControllerPath(route.getController().getClass());
              String template =  controllerPath + "/" + route.getActionName();
              RenderTemplateResponse resp = new RenderTemplateResponse(route.getController().values(), template, RequestContext.getFormat());
              if(!Configuration.getDefaultLayout().equals(controllerLayout)){
                  resp.setLayout(controllerLayout);//could be a real layout ot null for no layout
              }
              if(resp.getContentType() == null){
                  resp.setContentType(route.getController().getContentType());
              }
              RequestContext.setControllerResponse(resp);
              resp.setTemplateManager(Configuration.getTemplateManager());
      }
docs: this is implicit processing - default behavior, really