这样吧 public class test { public static void main(String[] args) { ArrayList<person> list = new ArrayList<>(2); list.add(new person(1)); person person1 = list.get(0); list.add(new person(2)); list.add(new person(3)); person person2 = list.get(0); System.out.println(person1==person2); } static class person{ private Integer age; person(Integer age) { this.age=age;} } }