import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;


public class Main {

    /**
     * @param args
     * @throws Exception
     * @throws UnsupportedEncodingException
     */
    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        String pass = "blabla";
        String salt = "9B3AF463E1270DC5511D86293D23C0D1"; //Result suppose to be 535791F2391DCE9AD6FEBB9C49DC53FD

        byte[] decoded = new byte[salt.length() / 2];
        byte[] b_pass = pass.getBytes();
        for (int i = 0; i < decoded.length; i++) {
            decoded[i] = (byte) Integer.parseInt(salt.substring(i * 2, i * 2 + 2), 16);
        }

        byte[] b_combined = new byte[decoded.length + b_pass.length];
        System.arraycopy(decoded, 0, b_combined, 0, decoded.length);
        System.arraycopy(b_pass, 0, b_combined, decoded.length, b_pass.length);

        // get the MD5 digest library, not sure why this isn't just part of the jdk
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            // error handling here...
        }
        // add the bytes to our digest
        md5.update(b_combined);
        // get the digest bytes
        byte[] b_combined_hasehd = md5.digest();

        System.out.println(getHexString(b_combined_hasehd).toUpperCase()); //Result in 535791F2391DCE9AD6FEBB9C49DC53FD
    }

    public static String getHexString(byte[] b) throws Exception {
          String result = "";
          for (int i=0; i < b.length; i++) {
            result +=
                  Integer.toString( ( b[i] & 0xff ) + 0x100, 16).substring( 1 );
          }
          return result;
    }
}