Question

I am trying to get a hash value for a string using MessageDigest in Java, but the value is different every time. When I run the program twice it will again have completely different answers.

        MessageDigest md = null;

        try {
            md = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException nsae) {
        }

        md.update("string".getBytes());
        byte[] digest = md.digest();
        System.out.println(digest);

        md.reset();

        md.update("string".getBytes());
        byte[] digest2 = md.digest();
        System.out.println(digest2);

Answer 1

You are outputting the byte[] object, not the byte array contents. Use

System.out.println(Arrays.toString(digest1));
....
System.out.println(Arrays.toString(digest2));