第74題

Which two classes correctly implement both the java.lang.Runnable and the java.lang.Cloneable interfaces?
(Choose two.)
A. public class Session implements Runnable, cloneable {
public void run();
public Object clone();
}
B. public class Session extends Runnable, Cloneable {
public void run(){/* do something */}
public Object clone(){/* make a copy */}
}
C. public class Session implements Runnable, Cloneable {
public void run(){/* do something */}
public Object clone() {/* make a copy */}
}
D. public abstract class Session implements Runnable, Cloneable {
public void run(){/* do something */}
public Object clone(){/* make a copy */}
}
E. public class Session implements Runnable, implements Cloneable {
public void run(){/* do something */}
public Object clone() {/* make a copy */}
}
答案：CD
參考：7-6 介面

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哪兩個class 正確的實做 java.lang.Runnable 和 java.lang.Cloneable 介面.
Runnable 包含了一個 run() 的 method, Cloneable 有個 clone()的method
A.沒有實作method.
B.錯的關鍵字extends. (針對介面使用 implements)
C: 正確了使用implements的關鍵字 和 實做了 兩個 method, 有大括號 {} 就算實作.
D: 設定為abstract(抽象類別) 就可以實作或者不實作.
E. implements Runnable, implements Cloneable