code: public void setEnableWelcomeRoot(boolean enableFlag) throws Exception {
          final Address address = Address.root().add(SUBSYSTEM, SUBSYSTEM_WEB, VIRTUAL_SERVER, DEFAULT_HOST);
          final ModelNode req = createWriteAttributeRequest("enable-welcome-root", Boolean.toString(enableFlag), address);
          final ModelNode response = execute(req);
          if (!isSuccess(response)) {
              throw new FailureException(response);
          }
          return;
      }
docs: The enable-welcome-root setting controls whether or not to deploy JBoss'
  welcome-content application at root context. If you want to deploy your
  own app at the root context, you need to disable the enable-welcome-root setting
  on the default host virtual server. If you want to show the JBoss' welcome screen,
  you need to enable this setting.
  
  @param enableFlag true if the welcome screen at the root context should be enabled; false otherwise
  @throws Exception any error