Carthesian Product of N lists without allocations using lambda (forEach)

Main.java

import java.util.List;
import java.util.function.Consumer;

public class Main {
    public static void main(String[] args) {
        final List<Integer> l1 = List.of(1, 2, 3, 4, 5);
        final List<Double> l2 = List.of(1.1, 2.2, 3.3, 4.4, 5.5);
        final List<String> l3 = List.of("a", "b", "c", "d", "e");

        CarthesianProduct prod = new CarthesianProduct(l1, l2, l3);
        prod.forEach(System.out::println);
    }

    public static class CarthesianProduct {
        final private List<?>[] lists;
        final private int[] index;
        final private Object[] result;
        CarthesianProduct(List<?>... lists) {
            this.lists = lists;
            this.index = new int[lists.length];
            this.result = new Object[lists.length];
        }

        private void init(int length) {
            for (int i = 0; i < length; i++) {
                index[i] = 0;
                result[i] = lists[i].get(0);
            }
        }

        public void forEach(Consumer<List<?>> action) {
            // Initialize index and result
            init(lists.length);

            int pos = 0;
            while (pos < lists.length) {
                if (index[pos] < lists[pos].size()) {
                    result[pos] = lists[pos].get(index[pos]);
                    action.accept(List.of(result));
                    index[pos]++;
                    continue;
                }
                while (pos < lists.length && index[pos]+1 >= lists[pos].size()) {
                    pos++;
                }
                if (pos < lists.length) {
                    index[pos]++;
                    result[pos] = lists[pos].get(index[pos]);
                    init(pos);
                    pos = 0;
                }
            }
        }
    }
}