如何使用递归和非递归方式反转单向链表

class Node {
 char value;
 Node next;
}

public Node reverse(Node current) {
 //initialization
 Node previousNode = null;
 Node nextNode = null;

 while (current != null) {
  //save the next node
  nextNode = current.next;
  //update the value of "next"
  current.next = previousNode;
  //shift the pointers
  previousNode = current;
  current = nextNode;   
 }
 return previousNode;
}

public Node reverse(Node current)
 {
     if (current == null || current.next == null) return current;
     Node nextNode = current.next;
     current.next = null;
     Node reverseRest = reverse(nextNode);
     nextNode.next = current;
     return reverseRest;
 }