List<Integer> al = new ArrayList<>();
al.add(10);
al.add(20);
al.add(30);
al.add(1);
al.add(2);
// This makes a call to remove(index) and
// removes element 20.
al.remove(1);
// Now element 30 is moved one position back
// So element 30 is removed this time
al.remove(1);