code: public static String convertHexStringToString(String hexString) {
          String uHexString = hexString.toLowerCase();
          StringBuilder sBld = new StringBuilder();
          for (int i = 0; i < uHexString.length(); i = i + 2) {
              char c = (char)Integer.parseInt(uHexString.substring(i, i + 2), 16);
              sBld.append(c);
          }
          return sBld.toString();
      }
docs: Convert the hex string to string.
  
  @param hexString is the hex string.
  @return the string value that converted from hex string.