Printing all possible subsets of a list

Question

I have a List of elements (1, 2, 3), and I need to get the superset (powerset) of that list (without repeating elements). So basically I need to create a List of Lists that

Answer 1

Peter Minchev's solution modified to handle larger lists through BigInteger

public static List> getAllSubsets(List input) {
    BigInteger allMasks = BigInteger.ONE.shiftLeft(input.size());
    List> output = new ArrayList<>();
    for(BigInteger i=BigInteger.ZERO;allMasks.subtract(i).compareTo(BigInteger.ZERO)>0; i=i.add(BigInteger.ONE)) {
        List subList = new ArrayList();
        for(int j=0;j 0) {
                subList.add(input.get(j));
            }
        }
        System.out.println(subList);
        output.add(subList);
    }
    return output;
}