update: fix

Node.java

@@ -10,15 +10,15 @@ public class Node<T> {
         this.content = content;
     }
 
-    private T getContent() {
+    public T getContent() {
         return this.content;
     }
 
-    private void setNextNode(Node nextNode) {
+    public void setNextNode(Node nextNode) {
         this.nextNode = nextNode;
     }
 
-    private Node getNextNode() {
+    public Node getNextNode() {
         return this.nextNode;
     }
 }