reverse Linkedlist

//define linkedNode
class LinkedNode{
    int val;
    LinkedNode next;
    public LinkedNode(int val){
        this.val = val;
        this.next = next;
    }
}

class Solution{

    public static void main(String[] args) throws java.lang.Exception
    {
        LinkedNode head = new LinkedNode(1);
        LinkedNode node1 = new LinkedNode(2);
        LinkedNode node2 = new LinkedNode(4);
        LinkedNode node3 = new LinkedNode(5);
        LinkedNode node4 = new LinkedNode(7);
        head.next = node1;
        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        
        LinkedNode headtmp = head;
        System.out.print("Original list: ");
        while(head !=null){
            System.out.print(head.val);
            System.out.print("->");
            head = head.next;
        }
        System.out.print("null");
        
        
        System.out.println("Reversed list: ");
        
        head = reverse(headtmp);
        
        while(head !=null){
            System.out.print(head.val);
            System.out.print("->");
            head = head.next;
        }
        System.out.print("null");
    }
    
    public static LinkedNode reverse(LinkedNode head) {
        LinkedNode prev = null;
        while(head !=null){
            LinkedNode temp = head.next;
            head.next = prev;
            prev = head;
            head = temp;
        }
        return prev;
    }
}