Write a program in Java that can use a recursive backtracking to print all minimum size set covers for given set of items I and item subset S.

This algorithm will consider the set of candidate solutions consisting of all possible subsets of S. This algorithm should do the union of all item-subsets in the partial candidate solution plus the union of all remaining item-subsets that could be added to the candidate solution equal I and is the number of item subsets in the partial candidates solution less than or equal to the number of item-subsets in the best solution found so far.