[Java] Queue

import java.util.*;

public class Ex_Queue{
    public static void main(String args[]){
        Queue q = new LinkedList();
        q.offer("First");
        q.offer("Second");
        q.offer("Third");
       
        Object o;
        System.out.println(q.toString());
        while((o=q.poll())!=null){
            String s = (String)o;
            System.out.println(s);
        }
        System.out.println(q.toString());
    }
}




[First, Second, Third]
First
Second
Third
[]

因為每次用poll把queue內的元素取出,
所以最後是空的.