@Override
    public Queue<Integer> getImpl() {
      return new LinkedList<>();
    }

    private static final long serialVersionUID = 0;
  }

  public void testNewMultimapWithCollectionRejectingNegativeElements() {
    CountingSupplier<Set<Integer>> factory =
        new SetSupplier() {
          @Override
          public Set<Integer> getImpl() {
            final Set<Integer> backing = super.getImpl();