code: public String format(String key, Object... arguments) {
  		return MessageFormat.format(resourceBundle.getString(key), arguments);
  	}
docs: Get the message value from ResourceBundle by the key then format with the arguments.
  Example:<br>
  In resource file : msg=Hello {0}, today is{1}.<br>
  In java code : res.format("msg", "james", new Date()); <br>
  In freemarker template : ${_res.format("msg", "james", new Date())}<br>
  The result is : Hello james, today is 2015-04-14.