Glassfish Security - jdbcRealm: How to configure l

I use jdbcRealm for security in my glassfish v3.0.1 b22. It is set up so that it use the USER table inside my database for authentication by following this blog: http://blogs.oracle.com/foo/entry/mort_learns_jdbc_realm_authentication. I got it working fine, if I leave the digest algorithm as plain text. However when i try to use SHA-256 for digest algorithm, it stop working. What I did is specify in Glassfish - Security - Realm - jdbcRealm - digest that I want SHA-256 (I just type SHA-256 inside digest field). Then I wrote a simple Java program to convert password text into SHA-256 hash. I then paste that hash inside my password field in the database. By the way, password field is type varchar(30). I cant log in anymore. One thing I notice that my simple Java program generated different hash every time for the same text field.

Below are my simple java program:

        MessageDigest md = MessageDigest.getInstance("SHA-256");
        String text = "admin";
        md.update(text.getBytes("UTF-8"));
        byte[] digest = md.digest();
        System.out.println(digest.toString());

The jdbcRealm allows encoding values of hex or base64. You need to specify one of these in your realm configuration and in your code, convert the byte array into one of these formats:

Base64:

import com.sun.org.apache.xml.internal.security.utils.Base64;
...
byte[] digest = md.digest();
System.out.println(Base64.encode(digest));

Hex:

...
byte[] digest = md.digest();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < digest.length; i++) {
    String hex = Integer.toHexString(0xff & digest[i]);
    if (hex.length() == 1) sb.append('0');
    sb.append(hex);
}
System.out.println(sb.toString());