Funnily enough the way to make the code run properly was to remove the result class as the main function they did not call the result class, here is my code import java.io.; import java.math.; import java.security.; import java.text.; import java.util.; import java.util.concurrent.; import java.util.regex.*;

public class Solution {

static class SinglyLinkedListNode {
    public int data;
    public SinglyLinkedListNode next;

    public SinglyLinkedListNode(int nodeData) {
        this.data = nodeData;
        this.next = null;
    }
}

static class SinglyLinkedList {
    public SinglyLinkedListNode head;
    public SinglyLinkedListNode tail;

    public SinglyLinkedList() {
        this.head = null;
        this.tail = null;
    }

    public void insertNode(int nodeData) {
        SinglyLinkedListNode node = new SinglyLinkedListNode(nodeData);

        if (this.head == null) {
            this.head = node;
        } else {
            this.tail.next = node;
        }

        this.tail = node;
    }
}

public static void printSinglyLinkedList(SinglyLinkedListNode node, String sep, BufferedWriter bufferedWriter) throws IOException {
    while (node != null) {
        bufferedWriter.write(String.valueOf(node.data));

        node = node.next;

        if (node != null) {
            bufferedWriter.write(sep);
        }
    }
}


/*
 * Complete the 'insertNodeAtPosition' function below.
 *
 * The function is expected to return an INTEGER_SINGLY_LINKED_LIST.
 * The function accepts following parameters:
 *  1. INTEGER_SINGLY_LINKED_LIST llist
 *  2. INTEGER data
 *  3. INTEGER position
 */

/*
 * For your reference:
 *
 * SinglyLinkedListNode {
 *     int data;
 *     SinglyLinkedListNode next;
 * }
 *
 */

public static SinglyLinkedListNode insertNodeAtPosition(SinglyLinkedListNode llist, int data, int position) {

SinglyLinkedListNode newNode = new SinglyLinkedListNode(data);

if(position==0) {
    newNode.next = llist;
    return newNode;
}

SinglyLinkedListNode curr = llist;
for (int i = 0; i < position - 1 && curr != null; ++i) {
    curr = curr.next;
}

newNode.next=curr.next;
curr.next=newNode;

return llist;
}


private static final Scanner scanner = new Scanner(System.in);

public static void main(String[] args) throws IOException {
    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

    SinglyLinkedList llist = new SinglyLinkedList();

    int llistCount = scanner.nextInt();
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    for (int i = 0; i < llistCount; i++) {
        int llistItem = scanner.nextInt();
        scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

        llist.insertNode(llistItem);
    }

    int data = scanner.nextInt();
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    int position = scanner.nextInt();
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    SinglyLinkedListNode llist_head = insertNodeAtPosition(llist.head, data, position);

    printSinglyLinkedList(llist_head, " ", bufferedWriter);
    bufferedWriter.newLine();

    bufferedWriter.close();

    scanner.close();
}

}