Hello,

I am fairly new to java, roughly about three to four months in. I am having a problem with my java program. My goal is to request the user to enter how many times they want to roll a pair of dices. Each dice have numbers 1-6. When rolling the dices, I randomly pick a number from each dice and total the number. My goal is to calculate the number of times snake-eyes was rolled which is a total of 2 and total number of times a total of 7 was rolled. Here is my code. I am calling the rollDice method to perform the random pick and calculations. The error I am getting is at the bottom of the code. Any suggestions? Your help will be greatly appreciated.

package dice;

import java.util.Scanner;

import java.util.Random;

public class Dice

{

public static void main(String[] args)

{

int numRolls; // number of rolls

Scanner nord = new Scanner(System.in); // create InputStream

System.out.print("How many times would you like to roll the two dice? "); // prompt to enter how many times to roll dice

numRolls = nord.nextInt(); // variable to store number of rolls

// call rollDice method

rollDice(numRolls);

} //end main

public static void rollDice(int numRolls)

{

int d = numRolls;

int[] diceOne = null; // dice one variable

int[] diceTwo = null; // dice two variable

int crapsRolled = 0; // variable to hold how many times 7 was rolled

int snakeEysRolled = 0; // variable to hold how many times snake eyes was rolled

int totalDiceAmt; // count dice total

int[] diceRolls; // variable to store total number of dice rolls

int[] numArr = {1, 2, 3, 4, 5, 6}; // array to hold numbers on dice

// create an object from the Random class

Random r = new Random();

diceRolls = new int[d]; //create array to hold number of rolls

// loop through number of times you rolled

for (int i = 0; i < diceRolls.length; i++)

{

diceOne[i] = r.nextInt(numArr.length);

diceTwo[i] = r.nextInt(numArr.length);

totalDiceAmt = diceOne[i] + diceTwo[i];

// loop through number of times 2 was rolled

if (totalDiceAmt == 2)

{

snakeEysRolled++;

}

// loop through number of times 7 was rolled

if (totalDiceAmt == 7 )

{

crapsRolled++;

}

}

// print statement

System.out.println("Sneke Eyes was rolled " + snakeEysRolled + " times");

// print blank line

System.out.println();

System.out.println("Craps was rolled " + crapsRolled + " times");

} // end roll dice method

} // end Dice class

run:

How many times would you like to roll the two dice? 1000

Exception in thread "main" java.lang.NullPointerException

at dice.Dice.main(Dice.java:40)

Java Result: 1

BUILD SUCCESSFUL (total time: 4 seconds)