jdk 1.8中的list排序

　　 public static <T> void sort(List<T> list, Comparator<? super T> c) {
        list.sort(c);
    }
     
    public static <T extends Comparable<? super T>> void sort(List<T> list) {
        list.sort(null);
    }

    default void sort(Comparator<? super E> c) {
        Object[] a = this.toArray();
        Arrays.sort(a, (Comparator) c);
        ListIterator<E> i = this.listIterator();
        for (Object e : a) {
            i.next();
            i.set((E) e);
        }
    }