SCJP 1.6版考題 130

Given:
11. static void test(){
12.   try{
13.     String x = null;
14.     System.out.print(x.toString() + " ");
15.   }
16.     finally{System.out.print("finally ");}
17. }
18. public static void main(String[] args){
19.   try{test();}
20.   catch(Exception ex){System.out.print("exception ");}
21. }
 

What is the result?
 A. null
 B. finally
 C. null finally
 D. Compilation fails.
 E. finally exception

解答

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Ans: E

解說:

14行x.toString()錯誤，因為x是null，不能用null去操作一個不存在的物件方法toString
執行finally內的敘述之後，丟出nullPointerException例外回到main…
由20行的catch補捉此例外…