class Arrays2 {

    public static <T> T[] concat(T[] first, T[] second) {
        if (first == null)
            return second;
        else if (second == null)
            return first;
        T[] result = Arrays.copyOf(first, first.length + second.length);
        System.arraycopy(second, 0, result, first.length, second.length);
        return result;
    }

    private  Arrays2();

}