Keep getting out of bounds error and not randomizing correctly

Game of war!! text version
keep getting out of bounds error and it doesn't really shuffle the cards very well. please give advise new to programming.....Game of war!! text version against computer. I also need to split deck and play till playerA cards or playerB cards are gone.

import java.util.ArrayList;
import java.util.Random;
//import java.util.Vector;

public class cardWars 
{
		
	public static void main(String[] args) 
	{
		int cardIndex = 0;
		int playerAScore = 0;//computer
		int playerBScore = 0;//your
		int playerACard;//computer
		int playerBCard;//your
		int[] myCards = new int[52];
		//ArrayList<Integer> myCards = new ArrayList<Integer>();
		//ArrayList<Integer> playerADeck = new ArrayList<Integer>();
		//ArrayList<Integer> playerBDeck = new ArrayList<Integer>();
		//ArrayList<Integer> splitDeck = new ArrayList<Integer>();
		
		
		myCards = nIntegers(52);
		
		
		//Collections.shuffle(myCards);
		//split the deck 26 cards each playerADeck, playerBDeck....		
	do{
		//display cards
		System.out.print("Player A card:  ");
		playerACard = cardDisplay(myCards[cardIndex]);
		System.out.print("Player B card:  ");
		playerBCard = cardDisplay(myCards[cardIndex] + 1);					
		
			
		if (playerBCard > playerACard)
		{
		 System.out.println("Player B wins!");
		 playerBScore = playerBScore + 2;		 
		// System.out.println("Player B deck: " + playerBDeck);
		}
		else if (playerACard > playerBCard)
		{
		  System.out.println("Player A wins!");
		  playerAScore = playerAScore + 2;		  
		  //System.out.println("player a deck: " + playerADeck);
		}
		else
		{
		  System.out.println("It's a tie.");
		  playerBScore = playerBScore + 1;
		  playerAScore = playerAScore + 1;
		}
		
		System.out.println("Player A Score:   " + playerAScore);
		System.out.println("Player B Score: " + playerBScore);
		cardIndex = cardIndex + 2;
		System.out.println("There are " + (52 - cardIndex) + " cards remaining. ");	
					
		
	}
	while((52 - cardIndex)>0);
	System.out.println("Game Over!");	
	}//end main

	public static int[] nIntegers(int n) //Shuffles 
	{
		int nArray[] = new int[n];
		int temp, s;
		Random myRandom = new Random();
		//Initialize array
		for(int i = 0; i < n; i++)
		{
			nArray[i] = i;		
		}
		
		for(int i = n; i >= 1; i--)
		{
			s = myRandom.nextInt(i);
			temp = nArray[s];
			nArray[s] = nArray[i - 1];
			nArray [i - 1] = temp;			
		}
		return(nArray);
	}
	

	//Card Display
	public static int cardDisplay(int n)
	{
	//given card number n(0-51) prints & returns value
	String suit;
	String[] value = new String[13];//declare & create

	value[0] = "Two";
	value[1] = "Three";
	value[2] = "Four";
	value[3] = "Five";
	value[4] = "Six";
	value[5] = "Seven";
	value[6] = "Eight";
	value[7] = "Nine";
	value[8] = "Ten";
	value[9] = "Jack";
	value[10] = "Queen";
	value[11] = "King";
	value[12] = "Ace";
	
	//Determine suit adjust numeric value n
	
	if(n >= 0 && n <= 12)
	{
		suit = "Hearts";
	}
	else if (n >= 13 && n <= 25)
	  {
	    suit = "Diamonds";
	    n = n - 13;
	  }
	  else if (n >= 26 && n <= 38)
	  {
	    suit = "Clubs";
	    n = n - 26;
	  }
	  else 
	  {
	    suit = "Spades";
	    n = n - 39;
	  }
	  // print 
	  System.out.println(value[n] + " of " + suit);//prints value & suit
	  // return numeric value
	  return(n);	
	}

	
}