SupeDemo关键字的演示

 1 package oo.day04;
 2 //super演示
 3 public class SuperDemo {
 4     public static void main(String[] args) {
 5         Boo o = new Boo();
 6     }
 7 }
 8
 9 class Coo{
10     int c;
11     Coo(int c){
12         this.c = c;
13     }
14 }
15 class Doo extends Coo{
16     Doo(){
17         super(2);
18     }
19
20
21     /*
22     //如下代码为默认生成的代码，写不写都在那
23     Doo(){
24         super();
25     }
26     */
27 }
28
29
30
31
32
33
34
35
36
37
38
39
40 class Aoo{
41     int a;
42     Aoo(){
43         System.out.println("父类构造");
44     }
45 }
46 class Boo extends Aoo{
47     int b;
48     Boo(){
49         //super(); //默认，写不写都在那
50         System.out.println("子类构造");
51         //super(); //编译错误，必须位于子类构造的第1句
52     }
53 }