Stack.java

package com.basic;

public class Stack
{
	private ArrayList elementData = new ArrayList();

	public void push(Object o) {
		elementData.add(0, o);
	}

	public Object pop() {
		return elementData.remove(0);
	}

	public Object peek() {
		return elementData.get(0);
	}

	public boolean isEmpty() {
		return (elementData.size() == 0);
	}

	public int size() {
		return elementData.size();
	}
}