Ares·茂的博客

*接口Alarm（报警）拥有抽象方法void alarm() package step2; interface Alarm{ public void alarm(); } AlarmGuardDoor（防盗门）类继承了Door类，实现了接口Guard和接口Alarm package step2; public class AlarmGuardDoor extends Door implements Guard, Alarm{ public void open() {

Fruit类 package step1; public abstract class Fruit { protected String brand; public abstract void show(); } Apple类 package step1; public class Apple extends Fruit{ public Apple(){ this("黄金苹果"); } public Apple(String brand){