如果一个方法的参数是接口类型,就可以将任何实现该接口类的实例的引用传递给该接口参数,那么接口参数就可以回调类实现的接口的方法。
 
interface SpeakHello
 
{
 
 public void speakHello();
 
 }
 
 
 
class china implements SpeakHello
 
{
 
 public void speakHello()
 
 {
 
 System.out.println("china/n");
 
 }
 
}
 
class english implements SpeakHello
 
{
 
 public void speakHello()
 
 {
 
 System.out.println("english/n");
 
 }
 
}
 
class KindHello
 
{
 
 public void lookHello(SpeakHello hello)
 
 {
 
 hello.speakHello();
 
 }
 
}
 
public class hello {
 
 public static void main(String[] args) {
 
 // TODO Auto-generated method stub
 
 KindHello kh=new KindHello();
 
 kh.lookHello(new china());
 
 kh.lookHello(new english());
 
 }
 
}