Hi, I'm a beginner programmer and I keep getting stuck on this one
problem:
I try to make a new node:
   TreeNode newTree = new TreeNode(someitem(),somechild());
but, I keep getting null pointer exceptions on this line:
   Child.setItem(kids.head.listItem);
does that mean that either Child or  kids.head.listItem doesnt exist?

public class TreeNode {
 private Object item;
 private TreeNode Child;
 private TreeNode Sibling;
 public TreeNode(Object item, SList kids) {
   this.item = item;
    Child.setItem(kids.head.listItem);          //   this one
 }

public class SList {
 public SListNode head;
 public SList() {
   head = null;
 }
 public SList(SListNode head) {
   this.head = head;
 }

public class SListNode {
 public Object listItem;
 public SListNode next;
 public SListNode(Object item) {
   this.listItem = item;
 }