SCJP(OCPJP) 考古題解析 第１７題

Given:

public class Blip{
    protected int blipvert(int x){return 0;}
}
class Vert extends Blip{
    //insert code here
}

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：ＡＣＥＦＧ


解析：

Ｘ  B. private int blipvert(int x){return 0;} － 繼承來的方法存取只能更開放：public>protected>(default)>private

Ｘ  D. protected long blipvert(int x){return 0;} － Overriding不允許回傳不同型態