code: public static String calculateSHAHash(String s) throws
      NoSuchAlgorithmException, UnsupportedEncodingException
    {
      MessageDigest md = MessageDigest.getInstance("SHA-256");
      md.update(s.getBytes("UTF-8"));
      byte[] digest = md.digest();
  
      StringBuilder hashVal = new StringBuilder();
      for (byte b : digest)
      {
        hashVal.append(String.format("%02x", b));
      }
  
      return hashVal.toString();
    }
docs: Hashes a string using SHA-256.