Как создать мозаичную карту (у меня просто белый экран)

Мне нужна помощь в создании тайловой карты, я просто получаю белый экран вместо карты с изображениями (фрагментами) на нем. Может ли кто-нибудь помочь с этим?

World.java:

   package game.test.src;

   import java.awt.Graphics;
   import java.awt.Image;
   import java.awt.Rectangle;

   import javax.swing.ImageIcon;

    public class World {

private Rectangle[] blocks;
private Image[] blockImg;
private final int arrayNum = 500;

//Block Images
private Image BLOCK_GRASS, BLOCK_DIRT, BLOCK_STONE, BLOCK_SKY;

private int x, y;

public World(){
    BLOCK_GRASS = new ImageIcon("C:/Users/Pim/Desktop/2D game test/Game test 2/src/game/test/src/images/tile_grass").getImage();
    BLOCK_DIRT = new ImageIcon("C:/Users/Pim/Desktop/2D game test/Game test 2/src/game/test/src/images/tile_dirt").getImage();
    BLOCK_STONE = new ImageIcon("C:/Users/Pim/Desktop/2D game test/Game test 2/src/game/test/src/images/tile_stonek").getImage();
    BLOCK_SKY = new ImageIcon("C:/Users/Pim/Desktop/2D game test/Game test 2/src/game/test/src/images/tile_sky").getImage();
    blocks = new Rectangle[500];
    blockImg = new Image[500];
    
    loadArrays();
}

private void loadArrays()
{
    for(int i = 0; i < arrayNum; i++)
    {
        if(x >= 500){
            x = 0;
            y += 20;
        }
        if(i >= 0 && i < 100)
        {
            blockImg[i] = BLOCK_SKY;
            blocks[i] = new Rectangle(x, y, 20, 20);
        }
        if(i >= 100 && i < 125)
        {
            blockImg[i] = BLOCK_GRASS;
            blocks[i] = new Rectangle(x, y, 20, 20);
        }
        if(i >= 125 && i < 225)
        {
            blockImg[i] = BLOCK_DIRT;
            blocks[i] = new Rectangle(x, y, 20, 20);
        }
        if(i >= 225 && i < 500)
        {
            blockImg[i] = BLOCK_STONE;
            blocks[i] = new Rectangle(x, y, 20, 20);
        }
        x += 20;
        
    }
    
}

public void draw(Graphics g)
{
    for(int i = 0; i< arrayNum; i++){
        g.drawImage(blockImg[i], blocks[i].x, blocks[i].y, null);
    }
}   
}

А вот и GamePanel.java:

    package game.test.src;

import java.awt.*;
import java.awt.event.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JPanel;

public class GamePanel extends JPanel implements Runnable {
    //Double buffering
    private Image dbImage;
    private Graphics dbg;
    //JPanel variables
    static final int GWIDTH = 500, GHEIGHT = 400;
    static final Dimension gameDim = new Dimension(GWIDTH, GHEIGHT);
    //Game variables
    private Thread game;
    private volatile boolean running = false;
    //Game Objects
    World world;
    
    public GamePanel(){
        world = new World();
        
        setPreferredSize(gameDim);
        setBackground(Color.WHITE);
        setFocusable(true);
        requestFocus();
        //Handle all key inputs from user
        addKeyListener(new KeyAdapter(){
            @Override
            public void keyPressed(KeyEvent e){
                
            }
            @Override
            public void keyReleased(KeyEvent e){
                
            }
            @Override
            public void keyTyped(KeyEvent e){
                
            }
        });
        
    }
    
    public void run(){
        while(running){
            gameUpdate();
            gameRender();
            paintScreen();
            
        }
    }
    
    private void gameUpdate(){
        if(running && game != null){
            
        }
    }
    
    private void gameRender(){
        if(dbImage == null){ // Create the buffer
            dbImage = createImage(GWIDTH, GHEIGHT);
            if(dbImage == null){
                System.err.println("dbImage is still null!");
                return;
            }else{
                dbg = dbImage.getGraphics();
            }
        }
        //Clear the screen
        dbg.setColor(Color.WHITE);
        dbg.fillRect(0, 0, GWIDTH, GHEIGHT);
        //Draw Game elements
        draw(dbg);
    }
    
    /* Draw all game content in this method */
    public void draw(Graphics g){
        world.draw(g);
    }
    
    private void paintScreen(){
        Graphics g;
        try{
            g = this.getGraphics();
            if(dbImage != null && g != null){
                g.drawImage(dbImage, 0, 0, null);
            }
            Toolkit.getDefaultToolkit().sync(); //For some operating systems
            g.dispose();
        }catch(Exception e){
            System.err.println(e);
        }
    }
    
    public void addNotify(){
        super.addNotify();
        startGame();
    }
    
    private void startGame(){
        if(game == null || !running){
            game = new Thread(this);
            game.start();
            running = true;
        }
    }
    
    public void stopGame(){
        if(running){
            running = false;
        }
    }
    }

и Main.java:

package game.test.src;

import javax.swing.JFrame;

public class Main extends JFrame
{
    GamePanel gp;
    
    public Main()
    {
        gp = new GamePanel();
        setSize(500, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
        setResizable(false);
        add(gp);
    }
    

    
    public static void main(String[] args)
    {
        Main m = new Main();
    }

}