инспекция кода (крестики нолики)

Изучаю Джава, пока не понимаю кокой код "чистый", а какой... скажем так фиговый. Опытных кодеров прошу глянуть и подсказать что где подправить

enum ViewState {
    START_STATE, GAME_STATE;
}
class MyWindow extends JFrame{
    private static ViewState viewState;
    private static JPanel mainPanelBottom;
    private static JPanel mainPanelTop;
    private static JPanel setting;
    private static JPanel game;
    private static JPanel settingField;
    private static JFrame frame;
    private static JPanel gameBackground;
    private static JPanel gameField;
    public MyWindow(){
        frame = new JFrame();
        mainPanelBottom = new JPanel();                                     //Панель кнопок
        mainPanelTop = new JPanel();                                        //Панель стартовая и игры
        setting = new BottomPanelSetting();                                 
        game = new BottomPanelGame();
        settingField = new SettingField();
        gameField = new GameField();
        gameBackground = new GameBackground();
        frame.setSize(600, 700);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.setTitle("крестики нолики");
        mainPanelBottom.setLayout(new BorderLayout());
        mainPanelTop.setLayout(new BorderLayout());
        gameBackground.setPreferredSize(new Dimension(600,660));
        settingField.setPreferredSize(new Dimension(600,660));
        game.setPreferredSize(new Dimension(1,40));
        setting.setPreferredSize(new Dimension(1,40));
        settingField.setLayout(new BorderLayout());
        JPanel top = new JPanel();
        settingField.add(top, BorderLayout.NORTH);
        top.setPreferredSize(new Dimension(1, 50));
        top.setBackground(new Color(255, 127, 41));
        JPanel neTop = new JPanel();
        settingField.add(neTop, BorderLayout.SOUTH);
        neTop.setPreferredSize(new Dimension(1,250));
        neTop.setBackground(new Color(255, 127, 41));
        JPanel center = new JPanel();
        settingField.add(center, BorderLayout.CENTER);
        center.setLayout(new BoxLayout(center, BoxLayout.Y_AXIS));
        JPanel panelOne = new JPanel();
        JPanel panelTwo = new JPanel();
        panelOne.setBackground(Color.white);
        panelTwo.setBackground(Color.white);
        center.add(panelOne);
        center.add(panelTwo);
        JLabel settingOne = new JLabel("Жми играть");
        settingOne.setFont(new Font("Serif", Font.PLAIN, 28));
        panelOne.add(settingOne);
        gameBackground.setLayout(new BorderLayout());
        setting.setLayout(new GridLayout());
        game.setLayout(new GridLayout());
        gameBackground.setBackground(new Color(255, 246, 130));
        gameBackground.add(gameField, BorderLayout.CENTER);
        frame.getContentPane().add(BorderLayout.SOUTH, mainPanelBottom);
        frame.getContentPane().add(BorderLayout.CENTER, mainPanelTop);
        changeState(ViewState.START_STATE);
        frame.setVisible(true);
    }

    public static void changeState(ViewState state) {
        viewState = state;
        System.out.println("change state: " + viewState);
        switch (state) {
            case START_STATE:
                mainPanelBottom.removeAll();
                mainPanelTop.removeAll();
                mainPanelBottom.add(setting);
                mainPanelTop.add(settingField);
                mainPanelBottom.revalidate();
                mainPanelTop.revalidate();
                mainPanelBottom.repaint();
                mainPanelTop.repaint();
                break;
            case GAME_STATE:
                mainPanelBottom.removeAll();
                mainPanelTop.removeAll();
                mainPanelBottom.add(game);
                mainPanelTop.add(gameBackground);
                mainPanelBottom.revalidate();
                mainPanelTop.revalidate();
                mainPanelBottom.repaint();
                mainPanelTop.repaint();
                break;
            default:
                System.out.println("UNKNOWN STATE!");
                break;
        }
    }
}
class Main {
    public static void main(String[] args) {
        MyWindow start = new MyWindow();
    }
}

Класс с прорисовкой фигур

    public class GameField extends JPanel {
    private int width;
    private int height;
    private final int SIZE = 3;
    private int cellWidth;
    private int cellHeight;
    private char [][] map;
    private boolean moveX = true;
    int clX;
    int clY;
    public GameField() {
        setOpaque(false);
        map = new char[SIZE][SIZE];
        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                clX = e.getX() / cellWidth;
                clY = e.getY() / cellHeight;
                System.out.println((clX + 1) + " " + (clY + 1));
                if (map[clX][clY] == 0) { // only if empty cell
                    if (moveX) {
                        map[clX][clY] = 'x';
                    } else {
                        map[clX][clY] = 'o';
                    }
                    moveX = !moveX;
                    repaint();
                }
                if (isMapFull()){
                    System.out.println("ничья");
                    new Draw();
                }
                if (checkWin(map[clX][clY])){
                    System.out.println("кто-то выйграл");
                    new Win();
                }
            }
        });
    }
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g;
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        width = getWidth();
        height = getHeight();
        cellHeight = height/SIZE;
        cellWidth = width/SIZE;

        BufferedImage myPictureKrestic = null;
        try {
            myPictureKrestic = ImageIO.read(new File("pictures/krestic.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        BufferedImage myPictureNolik = null;
        try {
            myPictureNolik = ImageIO.read(new File("pictures/nolik.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }

        for (int i = 0; i < SIZE; i++) {
            g2d.setColor(Color.black);
            g2d.drawLine(0, i*cellHeight, width, i*cellHeight);
            g2d.drawLine(i*cellWidth,0,i*cellWidth,height);
        }
        for (int i = 0; i < SIZE; i++) {
            for (int j = 0; j < SIZE; j++) {
                if ((map[i][j] == 'x')) {
                    g2d.drawImage(myPictureKrestic, i * cellWidth, j * cellHeight, cellWidth, cellHeight, null);
                } else if ((map[i][j] == 'o')) {
                    g2d.drawImage(myPictureNolik, i * cellWidth, j * cellHeight, cellWidth, cellHeight, null);
                }
            }
        }
    }
    public boolean isMapFull(){
        for(int i=0; i < SIZE; i++){
            for(int j=0;j <SIZE; j++){
                if(map[i][j] == 0) return false;
            }
        }
        return true;
    }
    public boolean checkWin (char symb) {
        if(map[0][0] == symb && map[0][1] == symb && map[0][2] == symb) return true;
        if(map[1][0] == symb && map[1][1] == symb && map[1][2] == symb) return true;
        if(map[2][0] == symb && map[2][1] == symb && map[2][2] == symb) return true;
        if(map[0][0] == symb && map[1][1] == symb && map[2][2] == symb) return true;
        if(map[0][0] == symb && map[1][0] == symb && map[2][0] == symb) return true;
        if(map[0][1] == symb && map[1][1] == symb && map[2][1] == symb) return true;
        if(map[2][0] == symb && map[1][1] == symb && map[0][2] == symb) return true;
        if(map[0][2] == symb && map[1][2] == symb && map[2][2] == symb) return true;
        return false;
    }
}

остальные классы типа:

BottomPanelSetting(); BottomPanelGame(); SettingField(); GameField(); GameBackground()

не стал добавлять, т.к. почти пустые, если кому-то интересно, полностью проект можно глянуть тут - https://github.com/Zherikhov/TicTacToe