[問題] SCJP題庫第17題:override或overload ?

[aster30 (紫苑)]

Given:

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;}


答案B跟D錯  ACEFG對
B是因為繼承的方法權限只能更開放,故不能用private
但明明C也是private阿,為什麼C對?

D是因為overriding回傳型態要跟父類別相同
但明明F/G也改了回傳型別,為什麼對?


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→ Aztecs:因為CFG是overload吧
→ pzyc79:你標題不就寫了override or overload ,就overload啊...
→ Kennyq:看接收值，ABD是override，CEFG是overload
→ bleed1979:給原po keyword: Method Signature
推 nOhiTmE:因為參數long ，所以不是override