private static Boolean checkOIB(String oib) {

        if (oib.length() != 11)
            return false;

        try {
            Long.valueOf(oib);
        } catch (Exception e) {
            return false;
        }

        Integer a = 10;
        for (Integer i = 0; i < 10; i++) {
            a = a + Integer.valueOf(oib.substring(i, i+1));
            a = Math.mod(a, 10);
            if (a == 0)
                a = 10;
            a *= 2;
            a = Math.mod(a, 11);
        }
        Integer kontrolni = 11 - a;
        if (kontrolni == 10)
            kontrolni = 0;

        return kontrolni == Integer.valueOf(oib.substring(10));
    }