How do i get this display the rec

[ompu]

package Main2;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JPanel;

public class GamePanel extends JPanel implements Runnable{

    final int originalTileSize = 16; //16x16 tile
    final int scale = 3;

    final int tileSize = originalTileSize * scale; // 48x48
    final int maxScreenCol = 16;
    final int maxScreenRow = 12;
    final int screenWith = tileSize * maxScreenCol; //768 pixels
    final int screenHight = tileSize * maxScreenRow; //57 6pixels

    KeyHandler keyH = new KeyHandler();
    Thread gameThread;

        int playerX = 100;
        int playerY = 100;
        int playerspeed = 4;

    public GamePanel(){

        this.setPreferredSize(new Dimension(screenWith, screenHight ));
        this.setBackground(Color.black);
        this.setDoubleBuffered(true);
        this.addKeyListener(keyH);
        this.setFocusable(true);
    }

    public void startGameThread() {

        gameThread = new Thread(this);
        gameThread.start();
    }

    @Override
    public void run() {

        while(gameThread !=null){

            //System.out.println("The game loop is running");

            update();

            repaint();
        }

    }
   public void update() {

    if(keyH.upPressed == true) {
        playerY -= playerspeed;
    }
    if(keyH.downPressed == true) {
        playerY += playerspeed;
    }
    if(keyH.leftPressed == true) {
        playerX -= playerspeed;
    }
    if(keyH.rightPressed == true) {
        playerX += playerspeed;
    }

   } 
   public void painComponent(Graphics g) {

        super.paintComponent(g);

        Graphics2D g2 = (Graphics2D)g;

        g2.setColor(Color.white);

        g2.fillRect(playerX, playerY, tileSize, tileSize );

        g2.dispose();

   }
}

[Dani]

To display the rec? What is the red? The rectangle? What rectangle?

Your code isn't commented so it's confusing to someone seeing it for the first time what it's supposed to do and what it isn't doing correctly.