Solution to Calculate the hourglass sum for every hourglass in A, then print the maximum hourglass sum.

HourGlass

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution
{

    public static void main(String[] args) 
    {
        /* Create an input Scanner instance for reading input */
		Scanner stdIn = new Scanner(System.in);
		/* Name some constants used in the program */
		int rows = 6;				// Number of rows in the matrix
		int cols = 6;				// Number of columns in the matrix
		int minValueInArray = -9;	// Minimum value of an element in the matrix
		int elementsInHourGlass = 7;// Number of elements in an hourglass
		// Set max to the minimum hourglass sum possible
		int maxHourGlassSum = minValueInArray * elementsInHourGlass;
		// Declare the matrix of numbers
		int matrix[][] = new int[rows][cols];
		int hourGlassSum;	// Sum of the elements in the hourglass
		
		/* Read the values for the matrix looping thru the rows */
        for(int i=0; i < rows; i++)
        {
        	/* Loop thru the columns for each row, reading the matrix */
            for(int j=0; j < cols; j++)
            {
            	/* Read the next value from standard input */
                matrix[i][j] = stdIn.nextInt();
            }
        }
        /* For debugging, print out the matrix */
        for(int i=0; i < rows; i++)
        {
            for(int j=0; j < cols; j++)
            {
                //System.out.print(matrix[i][j] + " ");
            }
        }
        /* Loop thru the possible starting points of the hourglass */
        for (int i=0; i < (rows-2); i++) 
        {
        	for (int j=0; j<(cols-2); j++)
        	{
        		/* Print the hourglass starting position */
        		/* Print out the hourglass elements */
        		/* Compute the sum of the elements in the hourglass */
        		hourGlassSum = matrix[i][j]   + matrix[i][j+1]   + matrix[i][j+2] +
        									    matrix[i+1][j+1] +
        					   matrix[i+2][j] + matrix[i+2][j+1] + matrix[i+2][j+2];
        		/* Print out the sum of the elements in this hourglass */
        		/* Is the new hourglass sum greater than the max found so far */
        		if (hourGlassSum > maxHourGlassSum) 
        		{
        			/* If so, then replace the max hour glass sum, with the current sum */
        			maxHourGlassSum = hourGlassSum;
        		}
        	}
        }
        /* Print out the maximum hour glass sum */
        System.out.println( maxHourGlassSum);

    }
}

Well explained...