SCJP 1.6版考題 074

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 */}
   } 

解答

---

Ans: C D

解說:

此題問那二個類別正確地實作Runnable與Cloneable介面
A錯是因為既然實作了介面，就必須把介面中的抽象方法實作寫出來，run和clone方法依然是抽象的。
B錯是類跑不能用extends去繼承介面
E錯是寫法不對(要如C和D寫法)