URGENT. Java. can't. figure out why code isn't passing. I needed to do all the parts labeled 'TODO'

package solution;

import java.util.ArrayList;

/**

* PlayingCard.java

import java.util.Random;

/**

* The Deck represents a 52 PlayingCards in a deck.

* @version August 13, 2013

* @author Mitch Parry

*/

public class Deck

{

/**

* Number of cards.

*/

public static final int NUM_CARDS = 52;

private Random generator;

private ArrayList deck;

/**

* Constructor creates 52 cards and adds them to ArrayList deck.

*/

public Deck()

{

// Creates a random number generator to be used in shuffleDeck()

generator = new Random();

initialize();

}

/**

* Constructor uses a parameter to set the random seed.

*

* @param seed Seed for the random number generator.

*/

public Deck(int seed)

{

generator = new Random(seed);

initialize();

}

/**

* Initializes a sorted deck.

*/

public void initialize()

{

// TODO: Create the ArrayList that will hold the 52 cards

deck = new ArrayList();

// TODO: Add code here to create and add all cards to the deck.

// The resulting order should be from TWO CLUBS, TWO DIAMONDS,

// TWO HEARTS, TWO SPADES, THREE CLUBS, ..., ACE SPADES

for (int i = 0; i < SuitsAndRanks.NUMSUITS; i++)

{

for (int j = 0; j NUMSUITS; j++)

deck.add(new PlayingCard(

SuitsAndRanks.fetchRank(i),

SuitsAndRanks.fetchSuit(j))

);

}

}

/**

* Randomly shuffles the PlayingCard order in the ArrayList deck.

*/

public void shuffleDeck()

{

// TODO: Implement the shuffling algorithm: "...that picks a

// random card to go last, then a random card among the

// remaining cards to go second to last, then a random card

// among the remaining cards to go third to last, ...

for (int index = NUM_CARDS - 1; index > 0; index--)

{

// TODO: pick a random card to go last among the remaining

// (unshuffled) cards. Hint:

generator.nextInt(index + 1);

// TODO: swap

}

}

/**

* Returns the PlayingCard at the 'index' in the deck.

*

* @param index Index into the deck

* @return The PlayingCard at that 'index'.

*/

public PlayingCard getCard(int index)

{

// TODO return the playing card the 'index' in the deck.

return deck.get(index);

}

/**

* Returns a String representation of the Deck.

*

* @return The string.

*/

@Override

public String toString()

{

// TODO: Return a String with all the cards in the deck

// separated by an end line ' ' character.

String str = "";

for (PlayingCard card : deck)

{

str += card;

str += " ";

}

return str;

}

}