Untitled

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class SnakeGame extends JPanel implements ActionListener, KeyListener {

    private static final int WIDTH = 500;
    private static final int HEIGHT = 500;
    private static final int DOT_SIZE = 10;
    private static final int ALL_DOTS = 900;
    private static final int RAND_POS = 29;
    private static final int DELAY = 140;

    private Timer timer;
    private boolean inGame = true;
    private boolean leftDirection = false;
    private boolean rightDirection = true;
    private boolean upDirection = false;
    private boolean downDirection = false;
    private int dots;
    private int apple_x;
    private int apple_y;
    private int[] x = new int[ALL_DOTS];
    private int[] y = new int[ALL_DOTS];

    public SnakeGame() {
        addKeyListener(this);
        setBackground(Color.black);
        setFocusable(true);
        setPreferredSize(new Dimension(WIDTH, HEIGHT));
        initGame();
    }

    public void initGame() {
        dots = 3;
        for (int i = 0; i < dots; i++) {
            x[i] = 50 - i * 10;
            y[i] = 50;
        }
        locateApple();
        timer = new Timer(DELAY, this);
        timer.start();
    }

    public void locateApple() {
        Random random = new Random();
        apple_x = random.nextInt(RAND_POS) * DOT_SIZE;
        apple_y = random.nextInt(RAND_POS) * DOT_SIZE;
    }

    public void checkApple() {
        if ((x[0] == apple_x) && (y[0] == apple_y)) {
            dots++;
            locateApple();
        }
    }

    public void checkCollision() {
        for (int i = dots; i > 0; i--) {
            if ((i > 4) && (x[0] == x[i]) && (y[0] == y[i])) {
                inGame = false;
            }
        }
        if (y[0] >= HEIGHT) {
            inGame = false;
        }
        if (y[0] < 0) {
            inGame = false;
        }
        if (x[0] >= WIDTH) {
            inGame = false;
        }
        if (x[0] < 0) {
            inGame = false;
        }
    }

    public void move() {