1 package su;
 2
 3 class Instrument{
 4     public void play() {
 5         System.out.println("弹奏乐器");
 6     }
 7
 8     public void play2() {
 9         // TODO 自动生成的方法存根
10
11     }
12 }
13
14 class Wind extends Instrument{
15     public void play() {
16         System.out.println("弹奏Wind");
17     }
18     public void play2() {
19         System.out.println("调用Wind的play2");
20     }
21 }
22
23 class Brass extends Instrument{
24     public void play() {
25         System.out.println("弹奏Brass");
26     }
27     public void play2() {
28         System.out.println("调用Brass的play2");
29     }
30 }
31
32 public class WindBrass {
33     public static void tune(Instrument i) {
34         i.play();
35         i.play2();
36     }
37
38     public static void main(String[] args) {
39         // TODO 自动生成的方法存根
40         Wind w=new Wind();
41         tune(w);
42
43     }
44
45 }

 1 package su;
 2
 3 class monkey{
 4     public void speak(){
 5         System.out.println("咿咿呀呀.......");
 6     }
 7 }
 8
 9 class people extends monkey{
10     public void speak() {
11         System.out.println("小样的，不错嘛，会说话了！");
12     }
13     void think() {
14         System.out.println("别说话，认真思考");
15     }
16 }
17
18 public class ACE {
19     public static void main(String[] args) {
20         monkey m = new monkey();
21         people p1 = new people();
22         people p2 = new people();
23         m.speak();
24         p1.speak();
25         p2.think();
26     }
27
28 }