SCJP 1.6版考題 090

11. interface DeclareStuff{
12.   public static final int EASY = 3;
13.   void doStuff(int t);}
14.   public class TestDeclare implements DeclareStuff{
15.   public static void main(String[] args){
16.     int x = 5;
17.     new TestDeclare().doStuff(++x);
18.   }
19.   void doStuff(int s){
20.     s += EASY + ++s;
21.     System.out.println("s " + s);
22.   }
23. }


What is the result?
  A. s 14
  B. s 16
  C. s 10
  D. Compilation fails.
  E. An exception is thrown at runtime.

解答

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Ans: D

解說:

在DeclareStuff介面中宣告的doStuff方法存取屬性是public(在介面的方法存取屬性是public的)
TestDeclare要覆載doStuff方法，必須滿足overriding規則，19行需改為public void doStuff(int s)