package com.github.java8.lambdasinaction.chap9; import java.util.Arrays; import java.util.Comparator; import java.util.List; public class Intro{ public static void main(String...args){ List<Integer> numbers = Arrays.asList(3, 5, 1, 2, 6); // sort is a default method // naturalOrder is a static method numbers.sort(Comparator.naturalOrder()); System.out.println(numbers); } }