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SCJP 1.6版考題 063 - 修訂歷史
2026-05-29T22:46:03Z
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Ikk：新頁面: 11. class ClassA{} 12. class ClassB extends ClassA{} 13. class ClassC extends ClassA{} and: 21. ClassA p0 = new ClassA(); 22. ClassB p1 = new ClassB(); 23. ClassC p2 = new Class...
2013-03-30T06:58:39Z
<p>新頁面: 11. class ClassA{} 12. class ClassB extends ClassA{} 13. class ClassC extends ClassA{} and: 21. ClassA p0 = new ClassA(); 22. ClassB p1 = new ClassB(); 23. ClassC p2 = new Class...</p>
<p><b>新頁面</b></p><div> 11. class ClassA{}<br />
12. class ClassB extends ClassA{}<br />
13. class ClassC extends ClassA{}<br />
and:<br />
21. ClassA p0 = new ClassA();<br />
22. ClassB p1 = new ClassB();<br />
23. ClassC p2 = new ClassC();<br />
24. ClassA p3 = new ClassB();<br />
25. ClassA p4 = new ClassC();<br />
<br />
<br />
Which three are valid? (Choose three.)<br />
A. p0 = p1;<br />
B. p1 = p2,<br />
C. p2 = p4;<br />
D. p2 = (ClassC)p1;<br />
E. p1 = (ClassB)p3;<br />
F. p2 = (ClassC)p4;<br />
<br />
<div class="toccolours mw-collapsible mw-collapsed"><br />
<span style="font-size:medium;">解答</span><br />
<br />
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<div class="mw-collapsible-content"><br />
<span style="font-size: medium;">Ans: A E F </span><br />
<br />
<span style="font-size:medium;"> 解說:<br />
B和C是A的子類別<br />
父類別的參考型態可以指向子類別態物件(因為子類別 is a 父類別)<br />
<br />
</span> <br />
</div></div><br />
{{SCJP 1.6版考題講解}}</div>
Ikk