get last n elements from list java

firstNum = numbers[0];
lastNum = numbers[numbers.length-1];

ArrayList<Integer> list = new ArrayList<Integer>(5); 
int last = list.get(list.size() - 1); 

List<Post> myLastPosts = posts.subList(posts.size()-40, posts.size());

List<E> tail = l.subList(Math.max(l.size() - 3, 0), l.size());