Hi im beginner programmer and this is my 2048 project but it dosent work and I cant understand whats the problem

See more:

Java

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
import javax.swing.JFrame;

public class MyGame extends JFrame implements KeyListener {


    private static final int size = 100;
    private Font font = new Font("TimesRoman", Font.BOLD, 20);
    private HashMap cLu = new HashMap() {
        {

            put(0, new Color(0xcdc1b4));
            put(2, new Color(0xeee4da));
            put(4, new Color(0xede0c8));
            put(8, new Color(0xf2b179));
            put(16, new Color(0xf59563));
            put(32, new Color(0xf67c5f));
            put(64, new Color(0xf65e3b));
            put(128, new Color(0xedcf72));
            put(256, new Color(0xedcc61));
            put(512, new Color(0xedc850));
            put(1024, new Color(0xedc53f));
            put(2048, new Color(0xedc22e));

        }
    };

    private int[][] grill = new int[4][4];

    public void init() {
        appear(1);
        addKeyListener(this);
    }

    private void appear(int h) {
        ArrayList available = new ArrayList<>();
        for (int i = 0; i = 0; j--) {
                    if (grill[i][j] == 0 && grill[i][j + 1] == 0) {
                        continue;
                    }
                    if (grill[i][j] == grill[i][j + 1]) {
                        grill[i][j + 1] = grill[i][j] * 2;
                        grill[i][j] = 0;
                    } else if (grill[i][j + 1] == 0) {

                        grill[i][j + 1] = grill[i][j];
                        grill[i][j] = 0;
                        j = grill[0].length - 1;

                    }

                }

            }

        } else if (m == KeyEvent.VK_LEFT) {

            for (int j = 0; j = 0; i--) {
                    if (grill[i][j] == 0 && grill[i + 1][j] == 0) {
                        continue;
                    }
                    if (grill[i][j] == grill[i + 1][j]) {
                        grill[i + 1][j] = 2 * grill[i][j];
                        grill[i][j] = 0;
                    } else if (grill[i + 1][j] == 0) {
                        grill[i + 1][j] = grill[i][j];
                        grill[i][j] = 0;
                        i = grill.length - 1;
                    }
                }
            }
        }

    }

    @Override
    public void paint(Graphics g) {
        g.clearRect(0, 0, grill.length, grill[0].length);
        FontMetrics fm = g.getFontMetrics();
        g.setFont(font);
        for (int i = 0; i < grill.length; i++) {
            for (int j = 0; j < grill[0].length; j++) {

                g.setColor(cLu.get(grill[i][j]));
                            g.fillRoundRect(i * size,  j * size, 95,95, 40, 40);
                //g.setColor(cLu.get(0));
               // g.drawRect(i * size, j * size, size, size);

                g.setColor(new Color(0x776e65));
                String number = String.valueOf(grill[i][j]);
                // center the number on top of the square
                int x = (i * size) + (size / 2) - (fm.stringWidth(number) / 2);
                int y = (j * size) + (size / 2) + (fm.getAscent() / 2);
                g.drawString(number, x, y);

            }
        }
    }

    @Override
    public void keyTyped(KeyEvent e) {
        int a = e.getKeyCode();
        if (a == KeyEvent.VK_UP || a == KeyEvent.VK_DOWN || a == KeyEvent.VK_RIGHT || a == KeyEvent.VK_LEFT) {
            move(a);
            appear(1);
            repaint();

        }
    }

    public static void main(String[] args)  {

        JFrame frame = new JFrame();
        MyGame m = new MyGame(); 
        frame.setVisible(true);
        frame.setTitle("2048");
        frame.setSize(410, 448);
        frame.setLocationRelativeTo(null);
        frame.add(m, BorderLayout.CENTER);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    @Override
    public void keyPressed(KeyEvent e) {

    }

    @Override
    public void keyReleased(KeyEvent e) {

    }
}

What I have tried:

i want to use the frame but it has Exception in thread "main" java.lang.IllegalArgumentException: adding a window to a container

pleas help me !
Thanks^-^