public static String computeDigest(URL url,String algorithm) throws IOException, NoSuchAlgorithmException {
  return computeDigest(url.openStream(),algorithm);
}

public static String computeDigest ( URL url , String algorithm ) throws IOException , NoSuchAlgorithmException { return computeDigest ( url . openStream ( ) , algorithm ) ; }
computes the message digest of data specified by a url .
