code: public static <DATATYPE> void addAllPermutations (@Nonnull @Nonempty final ICommonsList <DATATYPE> aInput,
                                                      @Nonnegative final int nSlotCount,
                                                      @Nonnull final Collection <ICommonsList <DATATYPE>> aResultList)
    {
      for (final ICommonsList <DATATYPE> aPermutation : new CombinationGenerator <> (aInput, nSlotCount))
        aResultList.add (aPermutation);
    }
docs: Fill a list with all permutations of the input elements.
  
  @param <DATATYPE>
  Element type to be combined
  @param aInput
  Input list.
  @param nSlotCount
  Slot count.
  @param aResultList
  The list to be filled with all permutations. Beware: this list may
  be quite large and may contain duplicates if the input list contains
  duplicate elements! Note: this list is not cleared before filling