Docker Invalid or corrupt jarfile /app/app.jar

У меня есть программа с 3 классами,

я пытаюсь сделать мультисборку но получаю ошибку!

Invalid or corrupt jarfile /app/app.jar в чем ошибка, голову сломал)

мой код `public class Main { public Main() { }

public static void main(String[] args) {
    Player bot = new Player();
    Player alex = new Player(VARIANTS.SCISSORS, "Alex");
    System.out.println(bot.whoWins(bot, alex));
}
   
Player {
private final String name;
private final VARIANTS variant;

public Player(VARIANTS variant, String name) {
    this.name = name;
    this.variant = variant;
}

public Player() {
    this.name = "Bot";
    this.variant = this.Random();
}

private VARIANTS Random() {
    int rnd = (int)(Math.random() * 3.0 + 1.0);
    VARIANTS var10000;
    switch (rnd) {
        case 1:
            var10000 = VARIANTS.PAPER;
            break;
        case 2:
            var10000 = VARIANTS.ROCK;
            break;
        default:
            var10000 = VARIANTS.SCISSORS;
    }

    return var10000;
}

public String whoWins(Player bot, Player human) {
    ArrayList<VARIANTS> arr = new ArrayList();
    arr.add(VARIANTS.ROCK);
    arr.add(VARIANTS.PAPER);
    arr.add(VARIANTS.SCISSORS);
    int index1 = arr.indexOf(bot.variant);
    int index2 = arr.indexOf(human.variant);
    if (index1 == index2) {
        return "Draw";
    } else {
        return index1 - index2 != 1 && index1 - index2 != -2 ? human.name + " Win!" : bot.name + " Win!";
    }
}

}

public enum VARIANTS {
ROCK,
PAPER,
SCISSORS;

private VARIANTS() {
}

}