Merge Two Sorted List

Java

class Solution {
	public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
			
	ListNode dummy = new ListNode(-1);
			ListNode tail = dummy;
			while (l1 != null && l2 != null) {
				if (l1.val > l2.val) {
				tail.next = l2;
				l2 = l2.next; 
				} else if (l1.val <= l2.val) {
				tail.next = l1;
				l1 = l1.next;
				}
				tail = tail.next;
			}
			if (l1 != null) {
				tail.next = l1;
			} else if (l2 != null) {
				tail.next = l2;
			}
			return dummy.next;
		}
}