All cases are OK, but the "congrulations" message does not appear.

public class Solution { public static void main(String[] args) throws IOException { BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

    List<List<Integer>> arr = new ArrayList<>();

    for (int i = 0; i < 6; i++) {
        String[] arrRowTempItems = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        List<Integer> arrRowItems = new ArrayList<>();

        for (int j = 0; j < 6; j++) {
            int arrItem = Integer.parseInt(arrRowTempItems[j]);
            arrRowItems.add(arrItem);
        }

        arr.add(arrRowItems);
    }
    int maxSum = Integer.MIN_VALUE;
    for (int i = 0; i < 5; i++) {    

        for (int j = 0; j < 5; j++){ 

            if(i+2 < arr.size() && j+2 < arr.get(i).size()){

                int sum = arr.get(i).get(j) + arr.get(i).get(j+1) 
                        + arr.get(i).get(j+2) + arr.get(i+1).get(j+1)
                        + arr.get(i+2).get(j) + arr.get(i+2).get(j+1) 
                        + arr.get(i+2).get(j+2);

                            maxSum = Math.max(maxSum, sum);
            }
        }
    }
    System.out.print(maxSum);

    bufferedReader.close();
}

}