对象应该长什么样子

 1 class Animal{
 2     String name;
 3     String food;
 4     int hunger;
 5     
 6     public void makeNoise(){}
 7     public void roam(){}
 8     
 9 }
10 
11 
12 public  class FirstDui extends Animal{
13     public void roam(){
14         System.out.println("犬类动物的活动方式！");
15     }
16     public static void main(String[] args){
17         FirstDui c = new FirstDui();
18         c.roam();
19     }
20 }