2D Array - DS Hackerrank Problem Solving Solution in JAVA8

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'hourglassSum' function below.
     *
     * The function is expected to return an INTEGER.
     * The function accepts 2D_INTEGER_ARRAY arr as parameter.
     */

    public static int hourglassSum(List> arr) {
    // Write your code here
        int sum=Integer.MIN_VALUE;
        
        for(int i=0;i<4;i++){
            for(int j=0;j<4;j++){
              int currentsum=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)
              ;
              sum=Math.max(currentsum,sum);
            }
        }
        return  sum;
    }

}

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

        List> arr = new ArrayList<>();

        IntStream.range(0, 6).forEach(i -> {
            try {
                arr.add(
                    Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                        .map(Integer::parseInt)
                        .collect(toList())
                );
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        });

        int result = Result.hourglassSum(arr);

        bufferedWriter.write(String.valueOf(result));
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}