JAVA program to swap head and tail of a linked list

CODE:

import java.util.Scanner;

public class swapHeadTail{

    static llistNode insert(llistNode H,int data){
        llistNode tmp = new llistNode();
        tmp.data=data;
        tmp.next=null;
        if(H==null)
            return tmp;
        llistNode curr = new llistNode();
        curr = H;
        while(curr.next != null)
            curr = curr.next;
        curr.next = tmp;
        return H;
    }

    public static void main(String[] args) {
        llistNode H = new llistNode();
        Scanner in = new Scanner(System.in);
        llistNode tmp =new llistNode();
       
        H=null;
        do{
            System.out.print("Enter data:");
            H=insert(H,in.nextInt());
            System.out.print("Enter 1 to continue: ");
        }while (in.nextInt()==1);
       
        tmp = H;
        while(tmp != null){
            System.out.print(tmp.data+"\t");
            tmp = tmp.next;
        }

        System.out.println();

        llistNode head = new llistNode();
        llistNode headNext = new llistNode();
        llistNode tailPrev = new llistNode();
        llistNode tail = new llistNode();

        head = H;
        headNext = H.next;
        tailPrev = H;
        while(tailPrev.next.next != null)
            tailPrev=tailPrev.next;
        tail = tailPrev.next;
        if ((tailPrev == head)&&(headNext == tail)){
            head.next = null;
            tail.next = head;
        }
        else{
            tmp = head;
            tmp.next = null;
            tailPrev.next = tmp;
            tail.next=headNext;
        }
        H=tail;
        tmp = H;
        while(tmp != null){
            System.out.print(tmp.data+"\t");
            tmp = tmp.next;
        }

    }
}

OUTPUT:

Enter data:1
Enter 1 to continue: 1
Enter data:2
Enter 1 to continue: 0
1    2  
2    1