如何合并两个有序链表

public class p合并有序链表 {
    public ListNode mergeTwoLists(ListNode list1,ListNode list2){
        ListNode cur1 = list1;
        ListNode cur2 = list2;
        
        ListNode newhead = new ListNode(-1);//定义一个假的头节点
        ListNode newlast = newhead;

        //进入循环的条件是链表是否为空
        while (cur1 !=null &&  cur2 != null){
            if (cur1.val<=cur2.val){
                //去cur1的结点，将cur1的结点尾插到newhead中
                newlast.next = cur1;
                cur1 = cur1.next;
            }else {
                newlast.next = cur2;
                cur2 = cur2.next;
            }
            newlast = newlast.next;
        }
        if(cur1 == null){
            newlast.next = cur2;
        }else{
            newlast.next = cur1;
        }
        return newhead.next;
    }
}