Merge a linked list into another linked list at alternate positions

// Java program to merge a linked list into another at
// alternate positions

import java.util.*;

class Node {
    int data;
    Node next;

    Node(int x) {
        data = x;
        next = null;
    }
}

class GfG {

    // Function to print a linked list
    static void printList(Node head) {
        Node curr = head;
        while (curr != null) {
            System.out.print(curr.data + " ");
            curr = curr.next;
        }
        System.out.println();
    }

    // Function to merge two linked lists
    static List<Node> merge(Node head1, Node head2) {
      
        // Initialize pointers to traverse the two lists
        Node temp1 = head1;
        Node temp2 = head2;

        // Traverse both lists and merge them
        while (temp1 != null && temp2 != null) {
          
            // Save the next nodes of the current nodes in
            // both lists
            Node ptr1 = temp1.next;
            Node ptr2 = temp2.next;

            // Insert the current node from the second list
            // after the current node from the first list
            temp2.next = temp1.next;
            temp1.next = temp2;

            // Update the pointers for the next iteration
            temp1 = ptr1;
            temp2 = ptr2;
        }

        return Arrays.asList(head1, temp2);
    }

    public static void main(String[] args) {

        // Creating first linked list 1->2->3
        Node head1 = new Node(1);
        head1.next = new Node(2);
        head1.next.next = new Node(3);

        // Creating second linked list 4->5->6->7->8
        Node head2 = new Node(4);
        head2.next = new Node(5);
        head2.next.next = new Node(6);
        head2.next.next.next = new Node(7);
        head2.next.next.next.next = new Node(8);

        // Store first and second head points in array
        List<Node> ar = merge(head1, head2);
        printList(ar.get(0));
        printList(ar.get(1));
    }
}