Java泛型实现一个栈

　　　在实现一个栈的时候，使用泛型有一下几个需要注意的点。

import java.util.Arrays;
import java.util.EmptyStackException;

public class MyStack<E> {
    private E[] element;
    private int size = 0;
    private static final int DEFAUL_INIT_CAPACITY = 16;

    @SuppressWarnings("unchecked")
    public MyStack() {
        element = (E[]) new Object[DEFAUL_INIT_CAPACITY];
    }

    public void push(E e) {
        ensureCapacity();
        element[size++] = e;
    }

    public E pop() {
        if (size == 0) throw new EmptyStackException();
        E result = element[--size];
        element[size] = null;
        return result;
    }

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

    private void ensureCapacity() {
        if (element.length == size) {
            element = Arrays.copyOf(element, 2 * size + 1);
        }
    }
}