Dynamic stack

public class DynamicStack {

    private class Node {

        Object element;
        Node next;

        public Node(Object element, Node next) {
            this.element = element;
            next.next = this;
        }

        Node(Object element) {
            this.element = element;
            this.next = null;
        }

    }

    public Node head;
    public Node tail;
    public int count;

    public DynamicStack() {
        this.head = null;
        this.tail = null;
        this.count = 0;
    }

    public void push(Object o) {
        if(head == null) {
            head = new Node(o);
            tail = head;
        } else {
            Node node = new Node(o, tail);
            tail = node;
        }
        count++;
    }

    public Object pop() {
        Object popedElement = tail.element;

        count--;
        if(count == 0) {
            tail = null;
            head = null;
        } else {
            int counter = 0;
            DynamicStack.Node iterator = head;
                while (counter != count) {
                    tail = iterator;
                    iterator = iterator.next;
                    counter++;
                }
        }

        return popedElement;
    }

    public Object peek() {
        return this.tail.element;
    }

    public int size() {
        return this.count;
    }



}