Think in Java - LinkedStack

package packinfo;


public class LinkedStack{
private static class Node{
U item;
Node next;
Node()
{
item = null;
next = null;
}
Node(U item, Node next)
{
this.item = item;
this.next = next;
}
boolean end()
{
return (item == null && next == null);
}
}

private Node top = new Node();
public void push(T item)
{
top = new Node(item, top);
}

public T pop()
{
T result = top.item;
if(!top.end())
{
top = top.next;
}
return result;
}

public static void main(String[] args)
{
LinkedStack lss = new LinkedStack();


for(String s : "Phasers on stun!".split(" "))
{
lss.push(s);
}

String s;
while((s = lss.pop()) != null)
{
System.out.println(s);
}
}
}