为什么倒数第一行里的add不能被调用啊

package test1;
import java.util.*;
public class BinarySortTree {
   public class node{
       int value;
       node next;
       public node(int value){
           this.value=value;
       }
       public void add(node node1){
           this.next=node1;
       }
       public void show(node node1){
           if(node1==null)return;
           else {
               show(node1.next);
               System.out.print(node1.value+" ");
           }
       }
   }
   public static void main(String [] args){
       BinarySortTree n=new BinarySortTree();
       Scanner sc=new Scanner(System.in);

       for(int i=0;i<5;i++){
           int a=sc.nextInt();
           n.add(n.new node(a));

       }

   }
}

package intersectionarrays;

import java.util.*;

import intersectionarrays.OuterClass.InnerClass;

public class BinarySortTree {
	public class node {
		int value;
		node next;

		public node(int value) {
			this.value = value;
		}

		public void add(node node1) {
			this.next = node1;
		}

		public void show(node node1) {
			if (node1 == null)
				return;
			else {
				show(node1.next);
				System.out.print(node1.value + " ");
			}
		}
	}

	public static void main(String[] args) {
		BinarySortTree n = new BinarySortTree();
		BinarySortTree.node bn = n.new node(0);
		Scanner sc = new Scanner(System.in);
		for (int i = 0; i < 5; i++) {
			int a = sc.nextInt();
			bn.add(n.new node(a));

		}
	}
}

import java.util.*;

class node {
	int value;
	node next;

	public node(int value) {
		this.value = value;
	}

	public void add(node node1) {
		this.next = node1;
	}

	public void show(node node1) {
		if (node1 == null)
			return;
		else {
			show(node1.next);
			System.out.print(node1.value + " ");
		}
	}

}

public class BinarySortTree2 {

	public static void main(String[] args) {
		node n = new node(0);
		Scanner sc = new Scanner(System.in);
		for (int i = 0; i < 5; i++) {
			int a = sc.nextInt();
			n.add(new node(a));

		}
	}
}

不使用内部类更简单