What will be the output of the following Java code snippet?

import java.util.*;
class Linkedlist 
{
    public static void main(String args[]) 
    {
        LinkedList obj = new LinkedList();
        obj.add("A");
        obj.add("B");
        obj.add("C");
        obj.addFirst("D");
        System.out.println(obj);
    }
}