Reverse a linked list

ListNode.java

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;
     }
  
    public static ListNode reverseList(ListNode l1) {
      ListNode curr = ln;
      ListNode prev = new ListNode(curr.val);
      while (curr.next != null) {
          prev = new ListNode(curr.next.val, prev);
          curr = curr.next;
      }
      return prev;
    }
 }