java泛型实现的一个简单stack

import java.util.Arrays;public class myStack<T> {    Object[] data;    private int capacity;    private int size;    public myStack()    {    capacity=16;    size=0;    data=new Object[capacity];    }    public void ensureCapacity(){    capacity=capacity*2;    data=Arrays.copyOf(data, capacity);    }    public void push(T ele)    {     if(size<capacity)    {    data[size++]=ele;    }    else    {    ensureCapacity();    data[size++]=ele;    }    }    public void pop()    {    if(size>0)    {    System.out.println(data[size-1]);    data[--size]=null;    }    else    {    System.out.println("Empty stack!");    }    }    boolean isEmpty()    {    return size==0;    }            public static void main(String[] args)    {    myStack<Integer> fcStack=new myStack<Integer>();    for(int i=0;i<10;i++)    {    fcStack.push(i);    }    for(int i=0;i<10;i++)    {    fcStack.pop();    }    fcStack.pop();    }}