Remove Duplicates from Sorted List 1

Remove Duplicates from Sorted List
Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
Time complexity is O(n);

public class Remove_Duplicates_from_Sorted_List1 {
 public class ListNode{
  int val;
  ListNode next;
  ListNode(int x) {
   val = x;
   next = null;
  }
 }
 public ListNode deleteDuplicates(ListNode head) {
        if (head == null) {
         return null;
        }
        ListNode node = head;
        while (node.next != null) {
         if (node.val == node.next.val) {
          node.next = node.next.next;
         } else {
          node = node.next;
         }
        }
        return head;
    }
}