Stack implementation in Java

Here's my implementation of a Stack in Java, all feedback welcome.

import java.util.Iterator;

public class Stack<T> implements Iterable<T> {
    private Node head = null;
    private int size;

    @Override
    public Iterator<T> iterator() {
        return new StackIterator();
    }

    private class Node<T>{

        public Node(T data){
            this.data = data;
            this.next = null;
        }
        T data;
        Node next;
    }

    private class StackIterator implements Iterator<T>{

        private Node current = head;
        @Override
        public boolean hasNext() {
            return current != null;
        }

        @Override
        public T next() {
            T item = (T) current.data;
            current = current.next;
            return item;
        }
    }

    public Stack(){
        size = 0;
        head = null;
    }

    public boolean isEmpty(){
        return head == null;

    }

    public void push(T item){
        Node p = new Node(item);
        if(head == null){
            head = p;
            size++;
            return;
        }
        p.next = head;
        head = p;
        size++;

    }

    public T pop(){
        Node current = head;
        if(current.next == null){
            head = null;
        }else{
            try {

                head = head.next;
                size--;
            }catch (Exception e){
                System.out.println("Popping off an empty stack:" + e);
            }
        }

        return (T)current.data;
    }


    public void trace(){
        Node current = head;
        while(current != null){
            System.out.println(current.data);
            current = current.next;
        }
    }
}