Shuffle a deck of cards in Java

Simply use a new array for the shuffled cards and fill it using random cards removed from the prior array.

import java.util.ArrayList;

public class Test {
    private static final int DECK_SIZE = 52;

    public static void main(String args[]) {
        ArrayList<Integer> deck = new ArrayList<Integer>();

        for (int i = 0; i < DECK_SIZE; ++i) {
            deck.add(i);
        }

        ArrayList<Integer> shuffledDeck = new ArrayList<Integer>();

        while (deck.size() > 0) {
            int index = (int) (Math.random() * deck.size());
            shuffledDeck.add(deck.remove(index));
        }

        System.out.println(shuffledDeck.toString());
    }
}

Or just use Collections.shuffle():

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

public class Test {
    private static final int DECK_SIZE = 52;

    public static void main(String args[]) {
        ArrayList<Integer> deck = new ArrayList<Integer>();

        for (int i = 0; i < DECK_SIZE; ++i) {
            deck.add(i);
        }

        Collections.shuffle(deck);

        System.out.println(deck);
    }
}

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