Exception array out of bounds

Question

My code needs to multiply each row of an array by each column of the next. The user inputs the height and width and the program will randomly generate the array values. It doesn't give any errors if the arrays are equal for example (3x3)(3x3) or even if you do (3x2)(2x3). if however you enter something like (3x3)(3x2) it gives an out of bounds exception.

public class Multiply {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        int width = -1;
        int height = 0;
        int width2 = 0;
        int height2 = 0;

        while (width != height2) {

            while (height <= 0) {
                System.out.print("Enter a height for array1: ");
                height = checkInt(scan);
            }

            while (width <= 0) {
                System.out.print("Enter a width for array1: ");
                width = checkInt(scan);
            }

            while (height2 <= 0) {
                System.out.print("Enter a height for array2: ");
                height2 = checkInt(scan);
            }

            while (width2 <= 0) {
                System.out.print("Enter a width for array2: ");
                width2 = checkInt(scan);
            }

            if (width != height2) {
                System.out
                        .println("Error! Dimensions of matrices not compatible. Try again.");
                width = -1;
                height = 0;
                width2 = 0;
                height2 = 0;
            }
        }

        int array1[][] = randomMatrix(height, width);
        int array2[][] = randomMatrix(height2, width2);
        int product[][] = matrixMultiply(array1, array2, height, width2);

        printArray(product);

    }// end of main method

    public static int[][] randomMatrix(int height, int width) {
        int array1[][] = new int[height][width];
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                array1[i][j] = (int) (-10 + Math.random() * 20);
            }
        }
        return array1;
    }// end of randomMatrix method

    public static int[][] matrixMultiply(int[][] array1, int[][] array2, int height, int width) {
        int[][] product = new int[height][width];
        for (int i = 0; i < array1.length; i++) {
            for (int j = 0; j < array1[i].length; j++) {
                int prod = 0;
                for (int k = 0; k < array2.length; k++) {
                    prod = prod + array1[i][k] * array2[k][j];
                }
                product[i][j] = prod;
            }
        }
        return product;
    }// end of matrixMultiply method

    public static void printArray(int[][] array) {
        System.out.println(" ");
        System.out.println("Row Major Representation:");

        for (int i = 0; i < array.length; i++) {
            for (int j = 0; j < array[i].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
        System.out.println(" ");
        System.out.println("Column Major Representation:");

        for (int i = 0; i < array[1].length; i++) {
            for (int j = 0; j < array.length; j++) {
                System.out.print(array[j][i] + " ");
            }

            System.out.println();
        }
    }

    public static int checkInt(Scanner scan) {
        int width = 0;
        if (scan.hasNextInt()) {
            width = scan.nextInt();
            return width;
        } else {
            scan.next();
            return 0;
        }

    }

}// end of public class Multiply

Answer 1

The value of the variable "j" (Line 82) in its final iteration is causing the Out of Bounds Exception. The error occurs for (3x3)(3x2) because in the final "j" iteration, j equals 2, making the value higher than 1 (the highest index value for j's location). Adding some logic to check for when j > the highest index will prevent the issue.