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();

     }

 }