java打印有序链表的公共部分(StreanTokenizer的简单用法)

但是最后面打印了空白符，不清楚为什么也通过测试！

package class04P;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;

public class Code03P_StreamTokennier {

    public static StreamTokenizer st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
    static int nextInt(){
        try{
            st.nextToken();
            return (int)st.nval;
        }catch(Exception e){
            e.printStackTrace();
        }

        return 0;
    }

    public static class Node{
        int val;
        Node next;

        public Node(int val){
            this.val = val;
        }
    }

    public static Node newlinkedList(int len){
        if(len == 0) return null;
        Node head = new Node(nextInt());

        Node cur = head;
        for (int i = 0; i < len - 1; i++) {
            cur.next = new Node(nextInt());
            cur = cur.next;
        }

        return head;
    }

    public static void printCommonPart(Node head1, Node head2){
        while(head1 != null && head2 != null){
            if(head1.val == head2.val){
                System.out.print(head1.val + " ");
                head1 = head1.next;
                head2 = head2.next;
            }
            else if(head1.val < head2.val){
                head1 = head1.next;
            } else if (head1.val > head2.val) {
                head2 = head2.next;
            }
        }
    }
    public static void main(String[] args) {
        Node head1 = newlinkedList(nextInt());
        Node head2 = newlinkedList(nextInt());

        printCommonPart(head1,head2);

    }
}