Leetcode-203: delete duplicate elements in linked list

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    
    
    public ListNode removeElements(ListNode head, int val) {
    
    
        ListNode dummyHead=new ListNode(-1);
        dummyHead.next=head;
        ListNode prev=dummyHead;
        while(prev.next !=null){
    
    
            if(prev.next.val==val){
    
    
                prev.next=prev.next.next;
            }
            else{
    
    
                prev=prev.next;
            }
        }
         return dummyHead.next;
    }
}