怎么在java项目中实现一个链栈存储

package com.learn.algorithm.linkStack;public class LinkStack<T> {  private LinkStack<T>.Node<T> top = new Node<T>();  private int size=0;      public boolean push(T t){        if ( isEmpty() ) {      top.next = new Node<T>(t);          } else {      Node<T> newNode = new Node<T>(t, top.next);      top.next = newNode;    }    size ++ ;    return true;  }      public T pop(){        if ( isEmpty() ) {      return null;    } else {      LinkStack<T>.Node<T> node = top.next;      top.next = node.next;      size --;      return node.getT();    }  }        public T getTop(){    if ( isEmpty() ) {      return null;    } else {      return top.next.getT();    }  }        public boolean isEmpty(){    return size() == 0;  }      public int size(){    return size;  }            class Node<T>{    private T t = null;    private Node<T> next = null;        public Node(){          }    public Node(T t){      this.t = t;    }    public Node(T t,Node<T> next){      this.t = t;      this.next =next;    }            public T getT() {      return t;    }    public void setT(T t) {      this.t = t;    }        public Node<T> getNext() {      return next;    }    public void setNext(Node<T> next) {      this.next = next;    }  }}