SCJP 1.6版考題 081

1. interface DoStuff2{
2.   float getRange(int low, int high);}
3.
4. interface DoMore {
5.   float getAvg(int a, int b, int c);}
6.
7. abstract class DoAbstract implements DoStuff2, DoMore{}
8.
9. class DoStuff implements DoStuff2{
10.   public float getRange(int x, int y){return 3.14f;}}
11.
12. interface DoAll extends DoMore{
13.   float getAvg(int a, int b, int c, int d);}


What is the result?
  A. The file will compile without error.
  B. Compilation fails. Only line 7 contains an error.
  C. Compilation fails. Only line 12 contains an error.
  D. Compilation fails. Only line 13 contains an error.
  E. Compilation fails. Only lines 7 and 12 contain errors.
  F. Compilation fails. Only lines 7 and 13 contain errors.
  G. Compilation fails. Lines 7, 12, and 13 contain errors.

解答

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Ans: A

解說:

此題可正確地編譯
說明：類別實作介面會繼承介面的抽象方法1．類別中有抽象的方法，該類別必須為抽象
2．類別若不為抽象，則必須對繼承的抽象方法提供實作