code: public static MD5Digest fromString(String md5String) {
      byte[] bytes;
      try {
        bytes = Hex.decodeHex(md5String.toCharArray());
        return new MD5Digest(md5String, bytes);
      } catch (DecoderException e) {
        throw new IllegalArgumentException("Unable to convert md5string", e);
      }
    }
docs: Static method to get an MD5Digest from a human-readable string representation
  @param md5String
  @return a filled out MD5Digest