{
                                 this.next.printNode();
                         }
                 }
         }
        
         private Node root;
         public void add(String name)
         {
                 Node newNode=new Node(name);
                 if(root==null)
                 {
                         this.root=newNode;
                 }
                 else
                 {
                         this.root.addNode(newNode);
                 }
         }
         public void print()
         {
                 if(root!=null)
                 {
                         this.root.printNode();
                 }
         }
}
class Test
{
         public static void main(String []args)
         {
                 Link l=new Link();
                 l.add("a");
                 l.add("b");
                 l.add("c");
                 l.add("d");
                 l.add("e");
                 l.add("f");
                 l.add("g");
                 l.print();
         }
}

private Link next;
这句有问题，只要改为private Node next;就可以了

果然是这样，编译器报错真不是随便看得懂