Remove Duplicates from Sorted List.java

https://leetcode.com/problems/remove-duplicates-from-sorted-list/
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode() {}
 *     ListNode(int val) { this.val = val; }
 *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {
      if(head == null || head.next == null){
          return head;
      }  
      ListNode node = head;
        while(head!=null && head.next!=null){
            if(head.val == head.next.val){
                head.next = head.next.next;
            }
            else{
                head = head.next;
            }
        }
        return node;
    }
}