The Matrix

import java.util.Arrays;
import java.util.Scanner;

public class TheMatrix {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter a size of matrix < 10");
        String input = scanner.nextLine().trim();
        int n;
        while (!input.matches("\\d+") || Integer.parseInt(input) >= 10) {
            System.out.println("The size must be numeric and less than 10. Try again: ");
            input = scanner.nextLine().trim();
        }
        n = Integer.parseInt(input);
        int[][] matrix1 = new int[n][n];
        int[][] matrix2 = new int[n][n];
        System.out.println("Enter the first matrix row by row. The elements must be eparated by ',': ");
        enterMatrix(matrix1);
        System.out.println("Enter the second matrix row by row. The elements must be eparated by ',': ");
        enterMatrix(matrix2);
        printTwoMatrixInParallel(matrix1, matrix2);
        printSumOFElements(matrix1, matrix2);
        printDirectSum(matrix1, matrix2);

    }

    public static void enterMatrix(int[][] matrix) {
        Scanner scanner = new Scanner(System.in);
        for (int i = 0; i < matrix.length; i++) {
            String[] inputArr = scanner.nextLine().split(",".trim());
            boolean isDigit = true;
            while (inputArr.length != matrix.length || Arrays.asList(inputArr).stream().anyMatch(element -> element.matches("\\D+"))) {
                System.out.printf("Try again! You should enter %d numeric elements: %n", matrix.length);
                inputArr = scanner.nextLine().split(",".trim());
            }
            for (int j = 0; j < inputArr.length; j++) {
                matrix[i][j] = Integer.parseInt(inputArr[j]);
            }
        }
    }

    public static void printTwoMatrixInParallel(int[][] firstMatrix, int[][] secondMatrix) {
        System.out.println("The both matrices are:");
        for (int i = 0; i < firstMatrix.length; i++) {
            for (int j = 0; j < firstMatrix.length; j++) {
                System.out.printf("%5d ", firstMatrix[i][j]);
            }
            System.out.print(" | ");
            for (int k = 0; k < firstMatrix.length; k++) {
                System.out.printf("%5d ", secondMatrix[i][k]);
            }
            System.out.println();
        }
        System.out.println();
    }

    public static void printSumOFElements(int[][] firstMatrix, int[][] secondMatrix) {
        System.out.println("The sum of elements is:");
        for (int i = 0; i < firstMatrix.length; i++) {
            for (int j = 0; j < firstMatrix.length; j++) {
                System.out.printf("%5d ", firstMatrix[i][j] + secondMatrix[i][j]);
            }
            System.out.println();
        }
        System.out.println();
    }

    public static void printDirectSum(int[][] firstMatrix, int[][] secondMatrix) {
        int n = firstMatrix.length;
        System.out.println("The direct sum is: ");
        for (int i = 0; i < n + n; i++) {
            for (int j = 0; j < n + n; j++) {
                if (i < n && j < n) {
                    System.out.printf("%5d ", firstMatrix[i][j]);
                }
                if (i < n && j >= n) {
                    System.out.printf("%5d ", 0);
                }
                if (i >= n && j < n) {
                    System.out.printf("%5d ", 0);
                }
                if (i >= n && j >= n) {
                    System.out.printf("%5d ", secondMatrix[i - n][j - n]);
                }
            }

            System.out.println();
        }
        System.out.println();
    }

}