Method with regex to check email format - Apex

Email Address Check - Regex.cls

public Boolean checkValidUsername(String emailAddress){
    String emailRegex = '([a-zA-Z0-9_\\-\\.]+)@((\\[a-z]{1,3}\\.[a-z]{1,3}\\.[a-z]{1,3}\\.)|(([a-zA-Z0-9\\-]+\\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})';
    Pattern MyPattern = Pattern.compile(emailRegex);

    Matcher MyMatcher = MyPattern.matcher(emailAddress);

    if(MyMatcher.matches()){
        return true;
    }else{
        return false;
    }
}