檢視 SCJP 1.6版考題 043 的原始碼

 1. class Plant{
 2.   private String name;
 3.   public Plant(String name){this.name = name;}
 4.   public String getName(){return name;}
 5. }
 6. public class Tree extends Plant{
 7.   public void growFruit(){}
 8.   public void dropLeaves(){}
 9. }
 
 
 What statement is true?
   A. The code will compile without changes.
   B. The code will compile if public Tree(){Plant();} is added to the Tree class.
   C. The code will compile if public Plant(){Tree();} is added to the Plant class.
   D. The code will compile if public Plant(){this("fern");} is added to the Plant class.
   E. The code will compile if public Plant(){Plant("fern");} is added to the Plant class.

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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:
Tree的預設建構子有super()，父類別必須有無參數的建構子

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{{SCJP 1.6版考題講解}}