Ikk：新頁面: 1. public class Blip{ 2. protected int blipvert(int x){return 0;} 3. } 4. class Vert extends Blip{ 5. //insert code here 6. } Which five methods, inserted independentl...

2013-03-30T08:40:36Z

新頁面: 1. public class Blip{ 2. protected int blipvert(int x){return 0;} 3. } 4. class Vert extends Blip{ 5. //insert code here 6. } Which five methods, inserted independentl...

新頁面

1. public class Blip{
2. protected int blipvert(int x){return 0;}
3. }
4. class Vert extends Blip{
5. //insert code here
6. }

Which five methods, inserted independently at line 5, will compile? (Choose five.)

A. public int blipvert(int x){return 0;}
B. private int blipvert(int x){return 0;}
C. private int blipvert(long x){return 0;}
D. protected long blipvert(int x){return 0;}
E. protected int blipvert(long x){return 0;}
F. protected long blipvert(long x){return 0;}
G. protected long blipvert(int x, int y){return 0;}

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<span style="font-size:medium;">解答</span>

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<span style="font-size: medium;">Ans: A C E F G </span>

<span style="font-size:medium;"> 解說:
這是考覆載的觀念，
在子類別中重寫(覆載)父類別的方法(方法名一樣，參數列一樣、回傳值型態一樣)，
必須要遵守子類別重寫的方法的存取屬性不能更封閉。

C/E/F/G 沒有問題是因為其參數不一樣，基本上就是不同的方法(overload，同名異式)
B錯，是因為開放性變小
D錯是因為回傳值型態不一樣。
(只要參數列一樣，就意謂是一樣的方法。)
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{{SCJP 1.6版考題講解}}

SCJP 1.6版考題 017 - 修訂歷史

Ikk：新頁面: 1. public class Blip{ 2. protected int blipvert(int x){return 0;} 3. } 4. class Vert extends Blip{ 5. //insert code here 6. } Which five methods, inserted independentl...