for (Integer i : list) {
            System.out.println(i);
        }

        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }

        Iterator<Integer> it = list.iterator();
        while (it.hasNext()) {
            int i = (Integer) it.next();
            System.out.println(i);
        }