public static String getMaxSubString(String s1, String s2) {
        String max, min;
        max = s1.length() > s2.length() ? s1 : s2;
        min = max == s1 ? s2 : s1;
        for (int x = 0; x < min.length(); x++) {
            for (int y = 0, z = min.length() - x; z != min.length() + 1; y++, z++) {
                String temp = min.substring(y, z);
                if (max.contains(temp))
                    return temp;
            }
        }
        return "";
    }