SCJP 1.6版考題 083

10. interface Foo{
11.   int bar();
12. }
13.
14. public class Beta {
15.
16. class A implements Foo{
17.   public int bar(){return 1;}
18. }
19.
20. public int fubar(Foo foo){return foo.bar();}
21.
22. public void testFoo(){
23.
24. class A implements Foo{
25.   public int bar() {return 2;}
26. }
 
27.
28. System.out.println(fubar(new A()));
29. }
30.
31. public static void main(String[] argv){
32.   new Beta().testFoo();
33. }
34. }
 

Which three statements are true? (Choose three.)
  A. Compilation fails.
  B. The code compiles and the output is 2.
  C. If lines 16, 17 and 18 were removed, compilation would fail.
  D. If lines 24, 25 and 26 were removed, compilation would fail.
  E. If lines 16, 17 and 18 were removed, the code would compile and the output would be 2.
  F. If lines 24, 25 and 26 were removed, the code would compile and the output would be 1.

解答

---

Ans: B E F

解說:

28行new A()，A類別是testFoo方法中定義的，所以回傳出2
若24~26移除，則使用的A類別是16~18定義的，回傳1