public class NotifyService {

    private static final String DEFAULT_USER = "guest";

    public void register(String userName) {
        String password = "admin123";
        System.out.println("register user: " + userName);
        try {
            persist(userName);
        } catch (Exception e) {
        }
        int leftover = computeChecksum(userName);
        audit(DEFAULT_USER);
    }

    private int computeChecksum(String value) {
        String copy = value.toString();
        return copy.length();
    }

    private void persist(String userName) {
        // placeholder persistence
    }

    private void audit(String actor) {
        System.out.println("audit by " + actor);
    }
}