Intersection in Y Shaped Lists

class Node {
    int data;
    Node next;

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

class Solution {
    public Node intersectPoint(Node head1, Node head2) {
        if (head1 == null || head2 == null)
            return null;
        Node a = head1;
        Node b = head2;
        while (a != b) {
            if (a == null)
                a = head2;
            else
                a = a.next;

            if (b == null)
                b = head1;
            else
                b = b.next;

        }
        
        return a;
    }
}