Merge Two Sorted 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) {
        
      ListNode head = new ListNode(0);
    	
    	ListNode temp = head;
    	 ListNode p = l1;
         ListNode q = l2;
         while(p!=null && q != null){
             
             if(p.val < q.val){
                 temp.next = p;
                 p = p.next;
                 temp = temp.next;
             }else{
                 temp.next = q;
                 q = q.next;
                 temp = temp.next;
             }
         }
         
         while(p != null){
             temp.next = p;
             p = p.next;
             temp = temp.next;
         }
         
         while(q != null){
             temp.next = q;
             q = q.next;
             temp = temp.next;
         }
         
         
         return head.next;
    }
}