Initialization Problem

Hi there,
i wanted to make a little chess game but there’s a Nullpointer-Exception.
I think the initialization order is the problem.

The nodes and materials are created in the Main class.

    private static ChessField chessField;
    public Material matBrownField;
    public Node chessFieldNode;

    public static void main(String[] args) {
        chessField = new ChessField();
        Main app = new Main();

    public void simpleInitApp() {

This is the derived ChessField class, where the NullPointerException is thrown at the chessFieldNode line:

public class ChessField extends Main{
    public ChessField(){
    private void makeWoodenFrame(){
        for (float x=0; 8>=x; x++) {
            chessFieldNode.attachChild(makeBox(new Vector3f(x, -.025f, 0), matBrownField));

What’s the reason for the Exception?

How many applications do you want in your application?

ChessField should absolutely not extend Main (which extends Application). You should learn how to pass what you need to your class instead of hoping (incorrectly) that fields magically get initialized just because you’ve extended some class.

That is correct. I converted the chessField class to a singleton, because there should be only one chess board.
I generate a lot of box objects, side-by-side. From the top the chess board looks nice, but from the side the wood texture looks kind of blurred.
Is there a possibility to configure this?