class StringUtils {

    public static String substringAfter(String str, String separator) {
        if ((str == null) || (str.length() == 0)) {
            return str;
        }
        if (separator == null) {
            return EMPTY;
        }
        int pos = str.indexOf(separator);
        if (pos < 0) {
            return EMPTY;
        }
        return str.substring(pos + separator.length());
    }

}