protected String validate(String emailAddress) {
        String REGEX = "^[_A-Za-z0-9-\\\\+]+(\\\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\\\.[A-Za-z0-9]+)*(\\\\.[A-Za-z]{2,})$\n";

        if (emailAddress == null) {
            throw new NullPointerException("Email Address cannot be null!");
        }

        if (!strictMode || emailAddress.matches(REGEX)) {
            return emailAddress;
        }

        throw new IllegalArgumentException("Invalid email address format specified: " + emailAddress);
    }