class Strings {

    public static String subStringAfterFirst(String str, String s) {
        if (isNullOrEmpty(str) || isNullOrEmpty(s))
            return str;
        final int pos = str.indexOf(s);
        if (pos < 0)
            return str;
        else return str.substring(pos + s.length());
    }

    private  Strings();

}