public static String md5(String... inputs) {
    try {
      String input = String.join(JOIN_DELIMITER, inputs);
      MessageDigest md5 = MessageDigest.getInstance(MD5_ALGORITHM);
      byte[] bytes = md5.digest(input.getBytes(StandardCharsets.UTF_8));
      return byteToString(bytes).toLowerCase(Locale.US);
    } catch (NoSuchAlgorithmException e) {
      throw new MaestroInternalError(e, "cannot find hash algorithm: " + MD5_ALGORITHM);
    }
  }
@Test
  public void testStringMD5() {
    String digest = HashHelper.md5("hello world");
    assertEquals("5eb63bbbe01eeed093cb22bb8f5acdc3", digest);
  }