Java 使用compareTo（）按字母顺序排序的列表

有人能帮我整理一下分类的链表吗。它应该按字母顺序打印东西。我有两个问题

1.当我在numNodes=1时添加第一个时，第一个自动消失（在本例中，Elaine消失）。 2.随后，应该是最后一项的项目仍然是第一项，而其余的项目则安排得很好

101 public void addOrdered(E item) {
102         ListNode<E> newNode = new ListNode<E> (item, null);
103         if(numNodes == 0)   {
104             this.addFirst(item);
105             System.out.println(numNodes);
106             return;
107         }
108         else if(numNodes == 1)  {
109             ListNode<E> curr = head;
110             // if alphabetically in front, add in front
111             if((newNode.getElement()).compareTo(curr.getElement())<0)   {
112                 System.out.println("ADD IN FRONT");
113                 this.addFirst(item);
114                 return;
115             }   
116             // if alphabetically behind, add behind
117             else    {
118                 System.out.println("ADD IN BEHIND");
119                 curr.setNext(newNode);
120             }   
121         }   
122         else    { //find position to add in between
123             ListNode<E> curr = head.getNext(), prev = head;
124             while((curr != null) && ((newNode.getElement()).compareTo(curr.getElement())>0 ))   {
125                 prev = curr;
126                 curr = curr.getNext();
127             }   
128             newNode.setNext(curr);
129             prev.setNext(newNode);
130         }   
131         numNodes++;
132             System.out.println(numNodes);
133     }       
134 }  

我的输出是

1
[Elaine]
ADD IN FRONT
[Diana]
3
[Diana, Avery]
4
[Diana, Avery, Candy]
5
[Diana, Avery, Bubble, Candy]
List: 
[Diana, Avery, Bubble, Candy]

---

使用node==null而不是node==0进行比较。珠心指向什么？

1
[Elaine]
ADD IN FRONT
[Diana]
3
[Diana, Avery]
4
[Diana, Avery, Candy]
5
[Diana, Avery, Bubble, Candy]
List: 
[Diana, Avery, Bubble, Candy]