all possible combination of n sets

Question

I have n Sets. each Set has different number of elements. I would like to write an algorithm which give me all possible combinations from the sets. for example: Lets say we have

Answer 1

In the case someone wants the matrix instead of printing, I slightly modified the code:

public class TestSetCombinations2 {

    public static void main(String[] args) {
        Double[] set1 = {2.0,3.0};
        Double[] set2 = {4.0,2.0,1.0};
        Double[] set3 = {3.0, 2.0, 1.0, 5.0};
        Double[] set4 = {1.0,1.0};
        Object[][] sets = {set1, set2, set3, set4};

        Object[][] combinations = getCombinations(sets);

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

    private static Object[][] getCombinations(Object[][] sets) {

      int[] counters = new int[sets.length];
        int count = 1;   
        int count2 = 0;

        for (int i = 0; i < sets.length; i++) {
          count *= sets[i].length;
        }

        Object[][] combinations = new Object[count][sets.length];

        do{
           combinations[count2++] = getCombinationString(counters, sets);
        } while(increment(counters, sets));

        return combinations;
    }

    private static Object[] getCombinationString(int[] counters, Object[][] sets) {

      Object[] o = new Object[counters.length];
      for(int i = 0; i=0;i--) {
            if(counters[i] < sets[i].length-1) {
                counters[i]++;
                return true;
            } else {
                counters[i] = 0;
            }
        }
        return false;
    }
}