code: protected String getRequiredMessage(final String[] messageKeys) {
  		MessageSourceResolvable resolvable = new MessageSourceResolvable() {
  
  			public String[] getCodes() {
  				return messageKeys;
  			}
  
  			public Object[] getArguments() {
  				return null;
  			}
  
  			public String getDefaultMessage() {
  				if (messageKeys.length > 0) {
  					return messageKeys[0];
  				}
  				return "";
  			}
  		};
  		return getMessages().getMessage(resolvable);
  	}
docs: Get the message for the given key. Don't throw an exception if it's not
  found but return a default value.
  
  @param messageKeys The keys to use when looking for the message.
  @return the message found in the resources or a default message.