程序代码：

class Super{   
   static String greeting(){   
      return "Good night";   
  }   
  
  String name(){   
     return "Richard";   
  }   
}   
  
class Sub extends Super{   
   static String greeting(){   
     return "Hello";   
  }   
  
  String name(){   
     return "Dick";   
  }   
}   
  
class Test{   
  public static void main(String[] args){   
    Super s = new Sub();   
    System.out.println(s.greeting()+","+s.name());   
  }   
}