java set collection list LinkedList details

As follows:

import java.util.*;

/*
LinkedList: Specific methods: 
addFirst();
addLast();

getFirst();
getLast();
 Gets the element, but does not delete it. If there is no element in the set, it will appear NoSuchElementException

removeFirst();
removeLast();
 Gets the element, but the element is deleted. If there is no element in the set, it will appear NoSuchElementException


 in JDK1.6 Alternatives have emerged. 

offerFirst();
offerLast();


peekFirst();
peekLast();
 Gets the element, but does not delete it. If there is no element in the collection, it returns null . 

pollFirst();
pollLast();
 Gets the element, but the element is deleted. If there is no element in the collection, it returns null . 




*/

class LinkedListDemo 
{
 public static void main(String[] args) 
 {
  LinkedList link = new LinkedList();

  link.addLast("java01");
  link.addLast("java02");
  link.addLast("java03");
  link.addLast("java04");

  //sop(link);
//  sop(link.getFirst());
//  sop(link.getFirst());
  //sop(link.getLast());
  //sop(link.removeFirst());
  //sop(link.removeFirst());

  //sop("size="+link.size());

  while(!link.isEmpty())
  {
   sop(link.removeLast());
  }

 }

 public static void sop(Object obj)
 {
  System.out.println(obj);
 }
}
/*

---
java01
java02
java03
java04

----
java04
java03
java02
java01
---
*/