Merge Two Sorted Lists

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
      ListNode root=null;
        if(l1==null)
            return l2;
        if(l2==null)
            return l1;
        
        if(l1.val>l2.val)
        {
            root=l2;
            root.next=mergeTwoLists(l1,l2.next);
            }
        else
        {
            root=l1;
            root.next=mergeTwoLists(l1.next,l2);
        }
        return root;
    }
}