JAVA题库求解

[lomyc]

Given:
10. class Line {
11. public class Point { public int x,y;}
12. public Point getPoint() { return new Point(); }
13. }
9
14. class Triangle {
15. public Triangle() {
16. // insert code here
17. }
18. }
Which code, inserted at line 16, correctly retrieves a local instance of a Point object?
A. Point p = Line.getPoint();
B. Line.Point p = Line.getPoint();
C. Point p = (new Line()).getPoint();
D. Line.Point p = (new Line()).getPoint();
Answer: D
Explanation:
为什么答案是D呢，求详细解答谢谢

[飏飏一蝶]

point是非静态内部类，其存在依附于外部类，因此必须要先获得外部类的实例才能够实例化内部类；而内存类可见性声明是由外至内的，Outer.Inner形式。So D。

[nomasp]

Given:
10. class Line {
11. public class Point { public int x,y;}
12. public Point getPoint() { return new Point(); }
13. }
9
14. class Triangle {
15. public Triangle() {
16. // insert code here
17. }
18. }
Which code, inserted at line 16, correctly retrieves a local instance of a Point object?
A. Point p = Line.getPoint();
B. Line.Point p = Line.getPoint();
C. Point p = (new Line()).getPoint();
D. Line.Point p = (new Line()).getPoint();
Answer: D

楼上正解，我也没啥补充了……或者这样说 AB都没有new，C没有用Line.