Java - get all possible combinations of 2D array (each sub-array can have different size)

Quick solution:

public class CombinationsUtil {

    public static void printCombinations(int[][] mx, int position, String result) {
        if (position == mx.length) {
            System.out.println(result.substring(2));
            return;
        }
        for (int i = 0; i < mx[position].length; i++) {
            String newResult = result + ", " + mx[position][i];
            printCombinations(mx, position + 1, newResult);
        }
    }

    public static void main(String[] args) {
        int[][] mx = {
                {10, 20},
                {30, 40, 50}
        };
        printCombinations(mx, 0, "");
    }
}

Result:

10, 30
10, 40
10, 50
20, 30
20, 40
20, 50

Example 2

public class CombinationsUtilTest2 {

    public static void main(String[] args) {
        int[][] mx = {
                {10, 20, 30},
                {40, 50},
                {70, 80, 90}
        };
        CombinationsUtil.printCombinations(mx, 0, "");
    }
}

Result:

10, 40, 70
10, 40, 80
10, 40, 90
10, 50, 70
10, 50, 80
10, 50, 90
20, 40, 70
20, 40, 80
20, 40, 90
20, 50, 70
20, 50, 80
20, 50, 90
30, 40, 70
30, 40, 80
30, 40, 90
30, 50, 70
30, 50, 80
30, 50, 90