MyStack.java

package com.coding.basic;

import java.util.ArrayList;

public class MyStack {

	private ArrayList elementData = new ArrayList();
	
	public void push(Object o){		
	}
	
	public Object pop(){
		return null;
	}
	
	public Object peek(){
		return null;
	}
	public boolean isEmpty(){
		return false;
	}
	public int size(){
		return -1;
	}
}