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第六十六題：

Given:

5.    class Thingy{ Meter m = new Meter(); }
6.    class Component {void go() { System.out.print("c");}}
7.    class Meter extends Component {void go() { System.out.print("m"); }}
8.
9.    class DeluxeThingy extends Thingy {
10.        public static void main(String[] args) {
11.            DeluxeThingy dt = new DeluxeThingy();
12.            dt.m.go();
13.            Thingy t = new DeluxeThingy();
14.            t.m.go();
15.        }
16.    }

Which two are true? (Choose two.)

A. The output is mm.
B. The output is mc.
C. Component is-a Meter.
D. Component has-a Meter.
E. DeluxeThingy is-a Component.
F. DeluxeThingy has-a Component.

答案：ＡＦ

題目範圍：物件觀念

解析：

不論是Thingy物件還是DeluxeThingy物件，都使用Meter中的方法

第六十七題：

Given:

10. abstract public class Employee {
11.     protected abstract double getSalesAmount();
12.     public double getCommision() {
13.         return getSalesAmount() * 0.15;
14.     }
15. }
16. class Sales extends Employee {
17.     //insert method here
18. }

Which two methods, inserted independently at line 17, correctly complete the Sales class? (Choose two.)

A. double getSalesAmount() { return 1230.45; }
B. public double getSalesAmount() { return 1230.45; }
C. private double getSalesAmount() { return 1230.45; }
D. protected double getSalesAmount() { return 1230.45; }

答案：ＢＤ

題目範圍：物件觀念，抽象類別

解析：

抽象類別中需要被實作的方法，可見度等級只可以提升或相同，不可以降低

第六十八題：

Given the following six method names:

addListener
addMouseListener
setMouseListener
deleteMouseListener
removeMouseListener
registerMouseListener

How many of these method names follow JavaBean Listener naming rules?

A. 1
B. 2
C. 3
D. 4
E. 5

答案：Ｂ

題目範圍：命名規則

解析：

Listener可以被加在某物件上，因此會有addＸＸＸListener
移除Listener使用的是removeＸＸＸListener

因此正確的是addMouseListener和removeMouseListener

第六十九題：

Given:

11. public interface Status {
12.     /* insert code here */ int MY_VALUE = 10;
13. }

Which three are valid on line 12? (Choose three.)

A. final
B. static
C. native
D. public
E. private
F. abstract
C. protected

答案：ＡＢＤ

題目範圍：介面interface

解析：

介面內變數的修飾，只允許final、static和public