Remove duplicates from sorted list II of leetcode topic resolution

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.

For example,

Given 1->2->3->3->4->4->5, return 1->2->5.

Given 1->1->1->2->3, return 2->3.

    public ListNode deleteDuplicates(ListNode head) {

        if (head == null) {
            return null;
        }

        if (head.next == null) {
            return head;
        }

        int val = head.val;

        ListNode node = head;

        boolean killme = false;

        while (node.next != null && node.next.val == val) {
            node = node.next;
            killme = true;
        }

        if (killme) {
            head = deleteDuplicates(node.next);
        } else {
            head.next = deleteDuplicates(node.next);
        }

        return head;
    }