LinkedList实现堆栈

    public?static?void?main(String[]?args)????{????????          MyStack?ms=new?MyStack();????????          ms.push("one");????????          ms.push("two");????????          ms.push("three");????????????????          System.out.println(ms.pop());????????          System.out.println(ms.pop());????????          System.out.println(ms.empty());????   }