Java: How to sort custom type ArrayList

Question

I have a custom type Position(x,y,z),now I create a ArrayList, i want to sort this array ordered by the value of z, from small to b

Answer 1

try

Collections.sort(SortList, new Comparator(){
            public int compare(Position p1, Position p2) {
                return p1.z- p2.z;
            }
        });