继承—Music

 public class Instrument {

     public void play(){
         System.out.println("弹奏乐器");
     }

 public class Wind extends Instrument {

     public void play(){
         System.out.println("弹奏Wind");
     }

     public void play2(){
         System.out.println("调用Wind的play2");
     }

 }

 public class Brass extends Instrument {

     public void play(){
         System.out.println("弹奏Brass");
     }
     public void play2(){
         System.out.println("调用Brass的play2");
     }

 }

 public class Music {
     public static void tune (Instrument i){
         i.play();
     }

     public static void main(String[] args) {

         Wind w=new Wind();
         tune(w);
         Brass b=new Brass();
         tune(b);
         b.play2();

     }

 }

结果：