public static void main(String[] args)
    {
        int[][] data = new int[2][2];
        int[][] data2 = new int[2][2];

        data[0][0] = 1;
        data[0][1] = 3;
        data[1][0] = 2;
        data[1][1] = 4;

        data2[0][0] = 0;
        data2[0][1] = 1;
        data2[1][0] = 5;
        data2[1][1] = 6;

        int[][] res = new int[2][2];
        res = mul(data,data2);

        for (int i = 0; i < res.length; i++)
        {
           for (int j = 0; j < res.length; j++) {
               System.out.print(res[i][j] + " ");
           }
            System.out.println();
        }
    }