Person.java ~~~ package obj.a2; public class Person { String name; String sex; int age=23; public void eat(){ System.out.println("正在吃飯"); } } ~~~ Test.java ~~~ package obj.a2; public class Test { public static void main(String[] args){ Person p1 =new Person(); System.out.println(p1.age); Person p2 =new Person(); p2.age=12; System.out.println(p2.age); } } ~~~