code: public static void addEndingSlashIfNeeded(StringBuilder src) {
  		if (src == null || StringUtils.isEmptyOrNull(String.valueOf(src))) {
  			return;
  		}
  		if (src != null
  				&& src.charAt(src.length() - 1) != File.separator.charAt(0)) {
  			src.append(File.separator);
  		}
  		return;
  	}
docs: <p>
  add the character ' /' at the end value
  </p>
  
  @param src