card-game/src/Pile.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;

public class Pile extends ArrayList<Card> {
    public static Pile createDeck(int numberOfCards) {
        Pile deck = new Pile();
        for (int number = 1; number <= numberOfCards; number++) {
            for (Card.Suit suit : Card.Suit.values()) {
                deck.add(new Card(number, suit));
            }
        }
        deck.shuffle();
        return deck;
    }

    public Pile getCardsForPlayer(int number) {
        Pile cardsForPlayer = new Pile();
        for (int i = 0; i < number; i++) {
            cardsForPlayer.add(get(0));
            remove(0);
        }
        return cardsForPlayer;
    }

    /**
     * Fisher-Yates shuffle()
     * https://stackoverflow.com/questions/1519736/random-shuffling-of-an-array
     */
    public void shuffle(Random random) {
        for (int i = this.size() - 1; i > 0; i--) {
            Collections.swap(this, i, random.nextInt(i + 1));
        }
    }

    public void shuffle() {
        Random random = new Random();
        shuffle(random);
    }

    public boolean uniqueMaximum(Card max, int maxIndex) {
        for (int i = 0; i < this.size(); i++) {
            if (maxIndex != i && max.number == this.get(i).number) {
                return false;
            }
        }
        return true;
    }
}