• + 73 comments

    I suggest

    import java.io.*;
    import java.util.*;
    
    public class Solution
    {
        public static void main(String[] args)
        {
            int a[][] = new int[6][6];
            int maxSum = Integer.MIN_VALUE;
            try (Scanner scanner = new Scanner(System.in);)
            {
                for(int i = 0; i < 6; i++)
                {
                    for(int j = 0; j < 6; j++)
                    {
                        a[i][j] = scanner.nextInt();
                        if (i > 1 && j > 1)
                        {
                            int sum =
                                a[i][j]
                                + a[i][j-1]
                                + a[i][j-2]
                                + a[i-1][j-1]
                                + a[i-2][j]
                                + a[i-2][j-1]
                                + a[i-2][j-2];
                            if (sum > maxSum) {maxSum = sum;}
                        }
                    }
                }
            }
            System.out.println(maxSum);
        }
    }
    

    It has the advantage to not run through the array a second time and instead calculate the results as soon as the data to do it is available.