【Java】CollectionクラスのComparator

Comparator…コレクションで全体順序付けを行う比較関数

Listの要素を昇順に並び替えたい

        public static void main(String[] args) {
            List<String> list = Arrays.asList("apple","melon","banana","cherry","orange");
            Collections.sort(list, Comparator.naturalOrder());
            System.out.println(list);
          }

Listの要素を降順に並び替えたい

        public static void main(String[] args) {
            List<String> list = Arrays.asList("apple","melon","banana","cherry","orange");
            Collections.sort(list, Comparator.reverseOrder());
            System.out.println(list);
          }