Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        ListNode listNode = new ListNode(0);
        ListNode pre = listNode;
        while (l1!=null&&l2!=null){
            if (l1.val<l2.val){
                pre.next = l1;
                l1 = l1.next;
            } else {
                pre.next = l2;
                l2 = l2.next;
            }
            pre = pre.next;
        }
        pre.next = l1==null?l2:l1;
        return listNode.next;
    }