print an array list in a list format in java w/o a loop

Question

I am trying to re-define the method toString(), which has to return a String, to print an array list called cards with type Card. Because toString() has to return a string I can't use a loop to print out each element one by one, yet I want to print the array list in a list format. Basically, does anyone know how to make toString() return the array list cards as a string without using a loop?

cards array list definition

    ArrayList <Card> cards = new ArrayList<Card>();

Card class creator

    Card card1 = new Card(String suit, String rank, int value);

toString method

    public String deckToString(){
        return cards;
    }

What it should print

[suit, rank, value]
[suit, rank, value]
[suit, rank, value]
[suit, rank, value]
 etc.

What it currently prints

[suit, rank, value] [suit, rank, value] etc.

Answer 1

If I understand correctly, you want each value on its own line. In other words, join the values by a line break, instead of by comma.

public String deckToString() {
    return String.join("\n", cards.stream().map(Card::toString).collect(Collectors.toList()));
}

Answer 2

  public String deckToString(){
            temp="";
            for (int i = 0;i<cards.length;i++){
                  temp+=cards.get(i)+"\n";
            return temp;
  }

This simply iterates through the cards and adds a newline for each card and adds it to the return string. This is similar to janos solution but is more visually simple.