testdeck | Object | Unit Testing library

I am trying to create a list of objects from a database but whenever I add another element to the end of the list it changes the values of the previous elements. I have seen similar questions on here but none seem to help my problem.

Here is the code for the class Deck

I am trying to develop a program that shuffles a deck by dividing the deck into two and then interlacing them.

Class Deck represents a deck of 52 cards. There are two methods: Deck(int n) and Card drawCard().

Deck(int n) is the constructor. The parameter tells how many rounds the deck should be shuffled. In each round of shuffling, the whole deck is first divided into two sub-decks. The sub-decks are then interlaced into one whole deck.

Some notes:

• To simplify the discussion, we assume the cards are 1, 2, …, 10.

• In the first round, the whole deck is divided into [1, 2, 3, 4, 5] and [6, 7, 8, 9, 10]. We then combine the two sub-decks by interlacing them to [1, 6, 2, 7, 3, 8, 4, 9, 5, 10].

• In the second round, we again divide the whole decks into two sub-decks [1, 6, 2, 7, 3] and [8, 4, 9, 5, 10] and then combine them to [1, 8, 6, 4, 2, 9, 7, 5, 3, 10].

• As we always put the cards in the first sub-deck before the second sub-deck, the first card and the last card of the deck remains the same no matter how many rounds we shuffle.

• The original order of the deck is S2, S3, …, SK, SA, H2, …, HA, C2, …, CA, D2, …, DA.

Card drawCard() removes the first card in the deck and returns it. Refer to the deck after the second round in the above discussion, drawCard() returns 1 and the deck becomes [8, 6, 4, 2, 9, 7, 5, 3, 10].

My method of interlacing: Create 3 array lists wherein 2 of them (cards1 and cards2) held the cards SA - HA and C2 - DA and the other (shuffled) held the interlaced deck. I managed to implement the original deck order, however when I try to interlace, I get an out of bounds error: "Index 0 out of bounds for length 0".

Question: What am I doing wrong?

Here are my codes: