Leetcode Remove Nth Node From End of List problem solution in Java

class Solution {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        // base case
        if (head.next == null) {
            return null;
        }
        
        //size of linkedlist
        int size = 0;
        ListNode curr = head;
        while (curr != null) {
            curr = curr.next;
            size++;
        }
        
        //removing SIZEth node from last i.e. head
           if(n == size) {
               return head.next;
           }

        
        // calculate the previous node before the nth node to be deleted
        int indexOfPrev = size - n;
        int i = 1;
        ListNode prev = head;
        while (i < indexOfPrev) {
            prev = prev.next;
            i++;
        }
        
        prev.next = prev.next.next;
        return head;
    }
}