Ikk：新頁面: Given a method that must ensure that its parameter is not null: 11. public void someMethod(Object value){ 12. //check for null value ... 20. System.out.println(value.getClass(...

2013-03-30T03:20:20Z

新頁面: Given a method that must ensure that its parameter is not null: 11. public void someMethod(Object value){ 12. //check for null value ... 20. System.out.println(value.getClass(...

新頁面

Given a method that must ensure that its parameter is not null:
11. public void someMethod(Object value){
12. //check for null value
...
20. System.out.println(value.getClass());
21. }

What, inserted at line 12, is the appropriate way to handle a null value?
A. assert value == null;
B. assert value != null : "value is null";
C. if (value == null){
throw new AssertionException("value is null");
}
D. if (value == null){
throw new IllegalArgumentException("value is null");
}

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<span style="font-size:medium;">解答</span>

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<span style="font-size: medium;">Ans: D </span>

<span style="font-size:medium;"> 解說:
value是公開的方法someMethod中的參數，此參數會由類別外部給予值，類別無法控制此值…
這種性質的參數測試不適合用asserttion(因assertion可以隨時關掉)

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{{SCJP 1.6版考題講解}}

SCJP 1.6版考題 139 - 修訂歷史

Ikk：新頁面: Given a method that must ensure that its parameter is not null: 11. public void someMethod(Object value){ 12. //check for null value ... 20. System.out.println(value.getClass(...