GamePanel.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

public class GamePanel extends JPanel implements ActionListener, KeyListener {

    private static final long serialVersionUID = 1L;
    ImageIcon ggwp;
    ImageIcon ground;
    ImageIcon steve;

    Timer timer = new Timer(5, this);
    int x = 10, y = 10, velX = 0, velY = 0, veldX = 0, veldY = 0;
    int playerSize = 27;
    int movmentSpeed = 3;
    int faildRounds;

    private Walls walls;
    private boolean running;
    private boolean nextMap = false;

    public GamePanel(int mapN) {
        timer.start();
        addKeyListener(this);
        setFocusable(true);
        setFocusTraversalKeysEnabled(false);
        running = true;
        walls = new Walls(mapN);
        ggwp = new ImageIcon(getClass().getClassLoader().getResource("ggwp.png"));
        this.setSize(817, 840);
        this.setLocation(100, 0);
        this.requestFocus(true);

    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        // Background;
        g.setColor(Color.cyan);
        g.fillRect(0, 0, getWidth(), getWidth());

        // Walls
        walls.draw(this, g);

        // Player
        if (running) {
            g.setColor(Color.blue);
            g.fillRect(x, y, playerSize, playerSize);
        }
        if (walls.wallsCollision(x, y, playerSize, playerSize)) {
            x = 10;
            y = 10;
        }
        if (walls.finishWallsCollision(x, y, playerSize, playerSize)) {
            running = false;
        }
        if (!running) {
            RoundFinishe(g);
        }

    }

    public void RoundFinishe(Graphics g) {
        if (!running) {
            g.setColor(Color.black);
            g.fillRect(0, 0, getWidth(), getHeight());
            ggwp.paintIcon(this, g, 280, 250);
            faildRounds++;
            nextMap = true;

        }
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int c = e.getKeyCode();
        if (running) {
            if (c == KeyEvent.VK_LEFT || c == KeyEvent.VK_A)
                veldX = -movmentSpeed;
            if (c == KeyEvent.VK_RIGHT || c == KeyEvent.VK_D)
                velX = movmentSpeed;
            if (c == KeyEvent.VK_UP || c == KeyEvent.VK_W)
                veldY = -movmentSpeed;
            if (c == KeyEvent.VK_DOWN || c == KeyEvent.VK_S)
                velY = movmentSpeed;
        }

    }

    @Override
    public void keyReleased(KeyEvent e) {
        int c = e.getKeyCode();
        if (running) {
            if (c == KeyEvent.VK_LEFT || c == KeyEvent.VK_A)
                veldX = 0;
            if (c == KeyEvent.VK_RIGHT || c == KeyEvent.VK_D)
                velX = 0;
            if (c == KeyEvent.VK_UP || c == KeyEvent.VK_W)
                veldY = 0;
            if (c == KeyEvent.VK_DOWN || c == KeyEvent.VK_S)
                velY = 0;
        }

    }

    @Override
    public void actionPerformed(ActionEvent e) {

        if (x < 0) {
            velX = 0;
            x = 0;
        }
        if (x > getWidth() - playerSize) {
            velX = 0;
            x = getWidth() - playerSize;
        }
        if (y < 0) {
            velY = 0;
            y = 0;
        }
        if (y > getHeight() - playerSize) {
            velY = 0;
            y = getHeight() - playerSize;
        }

        x += velX + veldX;
        y += velY + veldY;
        repaint();

    }

    @Override
    public void keyTyped(KeyEvent e) {
    }

}