public class Test4 {

     public static void main(String[] args){

         Instrument ss[]={new Wind(),new Piano()};

         for(Instrument i:ss){

             tun(i);

         }

     }

     public static void tun(Instrument i){

         i.play();

     }

} 

interface Instrument{

    void play();

}

class Wind implements Instrument{

    public void play(){

        System.out.println("wind can play");

    }

}

class Piano implements Instrument{

    public void play(){

        System.out.println("Piano can play");

    }

}