I need to fix this errors..

This are the two file codes:

import java.util.Optional;

public class LinkedListNode {

private V value;

private LinkedListNode next;

public LinkedListNode(V value, LinkedListNode next) {

this.value = value;

this.next = next;

}

public Optional> getNext() {

return Optional.ofNullable(next);

}

public V getValue() {

return value;

}

public LinkedListNode setValue(V value) {

this.value = value;

return this;

}

public LinkedListNode setNext(LinkedListNode next) {

this.next = next;

return this;

}

@Override

public String toString() {

return "LinkedListNode{" +

"value=" + value +

'}';

}

}

================================

import java.util.Optional;

public class LinkedList {

private LinkedListNode head;

public LinkedList() {

head = null;

}

public void addFront(V item) {

this.head = new LinkedListNode(item, head);

}

public void deleteFront() {

Optional> firstNode = Optional.ofNullable(this.head);

this.head = firstNode.flatMap(LinkedListNode::getNext).orElse(null);

firstNode.ifPresent(n -> n.setNext(null));

}

public Optional> find(V item) {

Optional> node = Optional.ofNullable(this.head);

while (node.filter(n -> n.getValue() != item).isPresent()) {

node = node.flatMap(LinkedListNode::getNext);

}

return node;

}

public void addAfter(LinkedListNode aNode, V item) {

aNode.setNext(new LinkedListNode(item, aNode.getNext().orElse(null)));

}

// write your code here

public String toString()

{

String s = "[";

LinkedListNode temp = head;

while(temp != null)

{

s += String.valueOf(temp.getValue());

if(temp != null)

{

s += ",";

}

}

s += "]";

return s;

}

public static void main(String[] args) {

LinkedList list = new LinkedList();

list.addFront("Isabel");

list.addFront("Ruth");

list.addFront("Karl");

list.addFront("John");

System.out.println(list.find("Isabel"));

System.out.println(list.find("Ruth"));

System.out.println(list.find("Karl"));

System.out.println(list.find("John"));

System.out.println(list.find("James"));

list.deleteFront();

System.out.println(list.find("John"));

list.addFront("Oliver");

System.out.println(list.find("Ruth"));

list.addAfter(list.find("Ruth").get(), "Sam");

System.out.println(list.toString());

LinkedListNode x = new LinkedListNode(5, null);

}

}

I believe the main problem is in the LinkedList.java where the public String toString() is, here are the errors:

10.00 out of 30.00 Use a while loop to traverse the linked list to add the nodes to print to the console. Wrap the list of nodes in opening and closing brackets separated by commas: [node1, node2, node3] . 1 out of 3 checks passed. Review the results below for more details. Checks Code Pattern Complete toString() contains a while loop Unit Test Incomplete toString() returns the nodes of the linked list as a String > Unit Test Incomplete toString() works as expected with the provided main() Unit Test Incomplete toString() returns the nodes of the linked list as a String Build Status Build Succeeded Test Output Test Contents @Test public void toStringUnitTest2() { LinkedList list = new LinkedList(); list.addFront("Taylor"); list. addFront("Bob"); list. addFront("Augusta"); list addFront("Sara"); list. addFront("Bob again"); assertEquals(list.toString(), "[Bob again, Sara, Augusta, Bob, Taylor]"); } Unit Test Incomplete toString() works as expected with the provided main() Build Status Build Succeeded Test Output Test Contents @Test public void toStringUnitTest1() { LinkedList list = new LinkedList(); list.addFront("Isabel"); list.addFront("Ruth"); list. addFront("Karl"); list. addFront("John"); list. deleteFront(); list.addFront("Oliver"); list.addAfter(list.find("Ruth").get(), "Sam"); assertEquals(list.toString(), "[Oliver, Karl, Ruth, Sam, Isabel]"); }