Reverse an ArrayList

 public ArrayList<Integer> reverse(ArrayList<Integer> list) {
       for(int i = 0, j = list.size() - 1; i < j; i++)
       {
          list.add(i, list.remove(j));
       }
       return list;
}

remove(int index)

Removes the element at the specified position in this list. Return the element.

add(E e)

Appends the specified element to the end of this list.

add(int index, E element)

Inserts the specified element at the specified position in this list.