public abstract class People {

 public abstract void yuyan();
}

public class China extends People {

 @Override
 public void yuyan() {
  // TODO Auto-generated method stub
  System.out.println("中国人说汉语");
 }
}

public class American extends People {

 @Override
 public void yuyan() {
  // TODO Auto-generated method stub
  System.out.println("美国人说英文");
 } 
}

public class InnerDeom {

 public static void main(String[] args) {
  // TODO Auto-generated method stub

   People p1 = new China();
   p1.yuyan();
   People p2 = new American();
   p2.yuyan();
 }
}

                                                        输出：

                                                                        中国人说汉语
                                                                        美国人说英文