How do I generate a Cartesian product in Java?

Question

I have a number of ArrayList with each ArrayList having objects and each one can have different length. I need to generate permutation like in the

Answer 1

Use Guava...here is an example of a Cartesian product of a list with itself:

public static void main(String[] args){
    //How to do a cartesian product of a List of items
    List listToSelfMultiply = Arrays.asList(new Integer(1), new Integer(2), new Integer(3), new Integer(4));
    LinkedList linkedListCopy = Lists.newLinkedList(listToSelfMultiply);
    for (Integer i:listToSelfMultiply) {
        if(linkedListCopy.size() == 1) {
            break;
        }
        linkedListCopy.remove();
        System.out.println("" + Arrays.deepToString(Lists.cartesianProduct(Arrays.asList(i), linkedListCopy).toArray()) + "");
    }
}