LeetCode 64 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.

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }
 */
public class Solution {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if(l1==null&&l2==null) return null;
        ListNode head=new ListNode(-1);
        ListNode pNode=head;
        while(l1!=null||l2!=null){
			if(l1==null) {
				pNode.next=l2;
				return head.next;
			}
			if(l2==null){
				pNode.next=l1;
				return head.next;
			}
            if(l1.val>l2.val){
				pNode.next=l2;
				l2=l2.next;
            }else {
				pNode.next=l1;
				l1=l1.next;
            }
            pNode=pNode.next;                   
        }
        return head.next;
    }
}