zaliczenie sudoku

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) throws FileNotFoundException {
        int[][] tar = new int[9][9];
        int isValid = 255;
        int suma_kol = 0;
        int suma_wie = 0;
        int sum_kwa = 0;
        System.out.println("program wczytuje sudoku z pliku");
        File plik = new File("sudoku.txt");
        Scanner odczyt = new Scanner(plik);


        while (odczyt.hasNextLine()) {
            for (int i = 0; i < 9; i++)
                for (int j = 0; j < 9; j++)
                    tar[i][j] = odczyt.nextInt();
        }

        for (int i = 0; i < 9; i++) {
            System.out.println(" ");
            for (int j = 0; j < 9; j++) {
                if (tar[i][j] == 0) {
                    System.out.print("  ");
                    isValid = 2;
                } else
                    System.out.print(" ");
                System.out.print(tar[i][j]);

            }
        }
        if (isValid == 2)
            System.exit(isValid);

        for (int j = 0; j < 9; j++)
        {
            int col = 0;
            for (int i = 0; i < tar.length; i++)
            {
                col = col + tar[j][i];
            }
            suma_kol = col;
            if (col != 45)
            {
                break;
            }
        }


        for (int j = 0; j < 9; j++)
        {
            int row = 0;
            for (int i = 0; i < tar.length; i++)
            {
                row = row + tar[i][j];
            }
            suma_wie = row;
            if (row != 45)
            {
                break;
            }
        }
        for (int j = 0; j < 9; j = j + 3)
        {
            for (int i = 0; i < 9; i = i + 3)
            {
                sum_kwa = tar[i][j] + tar[i][j + 1] + tar[i][j + 2] + tar[i + 1][j] + tar[i + 1][j + 1] + tar[i + 1][j + 2] + tar[i + 2][j] + tar[i + 2][j + 1] + tar[i +2][j + 2];
                if (sum_kwa != 45)
                {
                    break;
                }
            }
            if (sum_kwa != 45) {
                System.out.println(sum_kwa);
                break;

            }
        }

        if (suma_wie != 45 || suma_kol != 45 || sum_kwa != 45)
        {
            isValid = 1;
            System.exit(isValid);
        }
        isValid = 0;
        System.exit(isValid);


    }
}