private static void validateEmail(String email) throws TechnicalException {
        if (email == null || email.isEmpty() || email.length() > EMAIL_SIZE) {
            throw new TechnicalException(EMAIL_ERROR_MSG);
        }
        String regex = "\\w+@\\w+\\.[a-z]{2,}";
        Pattern p = Pattern.compile(regex);
        Matcher m = p.matcher(email);
        if (! m.matches()) {
            throw new TechnicalException(EMAIL_ERROR_MSG);
        }
    }