Spaceship Battle

package com.samkough.spaceshipbattle.main;

import javax.swing.JFrame;

@SuppressWarnings("serial")
public class Main extends JFrame
{
    public Main()
    {
        add(new Board());

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(400, 400);
        setLocationRelativeTo(null);
        setTitle("Spaceship Battle");
        setResizable(false);
        setVisible(true);
    }

    public static void main(String[] args)
    {
        new Main();
    }
}
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package com.samkough.spaceshipbattle.main;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JPanel;
import javax.swing.Timer;
import com.samkough.spaceshipbattle.entity.Craft;


@SuppressWarnings("serial")
public class Board extends JPanel implements ActionListener
{
    private Timer timer;
    private Craft craft;

    public Board()
    {
        addKeyListener(new TAdapter());
        setFocusable(true);
        setBackground(Color.BLACK);
        setDoubleBuffered(true);

        craft = new Craft();

        timer = new Timer(5, this);
        timer.start();
    }


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

        Graphics2D g2d = (Graphics2D)g;
        // In the paint() method, we draw the spacecraft. We get the image and the coordinates from the sprite class.
        g2d.drawImage(craft.getImage(), craft.getX(), craft.getY(), this);

        Toolkit.getDefaultToolkit().sync();
        g.dispose();
    }

    // The actionPerformed() method is called every 5ms. We move the sprite and repaint the board.
    public void actionPerformed(ActionEvent e)
    {
        craft.move();
        repaint();
    }


    private class TAdapter extends KeyAdapter
    {
        public void keyReleased(KeyEvent e)
        {
            craft.keyReleased(e);
        }

        public void keyPressed(KeyEvent e)
        {
            craft.keyPressed(e);
        }
    }

}
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/* This class represents a spacecraft. In this class we keep the image of the sprite and the coordinates of the sprite.
 * The keyPressed() and keyReleased() methods control whether the sprite is moving or is in standstill.
 */

package com.samkough.spaceshipbattle.entity;

import java.awt.Image;
import java.awt.event.KeyEvent;
import javax.swing.ImageIcon;

public class Craft
{

    private String craft = "craft.png";

    private int dx;
    private int dy;
    private int x;
    private int y;
    private Image image;

    public Craft()
    {
        ImageIcon ii = new ImageIcon(this.getClass().getResource(craft));
        image = ii.getImage();
        x = 40;
        y = 60;
    }

    // The move() method changes the coordinates of the sprite. These x, y values are used in the paint() method to draw the image of the sprite.
    public void move()
    {
        x += dx;
        y += dy;
    }

    public int getX()
    {
        return x;
    }

    public int getY()
    {
        return y;
    }

    public Image getImage()
    {
        return image;
    }

    public void keyPressed(KeyEvent e)
    {
        int key = e.getKeyCode();

        if (key == KeyEvent.VK_LEFT)
        {
            dx = -1;
        }

        if (key == KeyEvent.VK_RIGHT)
        {
            dx = 1;
        }

        if (key == KeyEvent.VK_UP)
        {
            dy = -1;
        }

        if (key == KeyEvent.VK_DOWN)
        {
            dy = 1;
        }
    }

    public void keyReleased(KeyEvent e)
    {
        int key = e.getKeyCode();

        // When we release the left cursor key, we set the dx variable to zero. The spacecraft will stop moving.
        if (key == KeyEvent.VK_LEFT)
        {
            dx = 0;
        }

        if (key == KeyEvent.VK_RIGHT)
        {
            dx = 0;
        }

        if (key == KeyEvent.VK_UP)
        {
            dy = 0;
        }

        if (key == KeyEvent.VK_DOWN)
        {
            dy = 0;
        }
    }
}