code: public void check() {
          getDispatcher().beforeCheck(this);
          
          RemoteWebElement e = (RemoteWebElement) getElement();
          while (!e.isSelected()) {
              e.click();
          }
          if (Config.getBoolConfigProperty(ConfigProperty.ENABLE_GUI_LOGGING)) {
              logUIAction(UIActions.CHECKED);
          }
          
          getDispatcher().afterCheck(this);
      }
docs: The CheckBox check function It invokes selenium session to handle the check action against the element.