### Question:
Results { public static Collector<Result,?,ResultList> listCollector() { return new ListCollector(); } private  Results(); static BasicResult create(long id, double score); static BasicResult basicCopy(Result r); static RescoredResult rescore(Result r, double s); static RescoredResult rescore(@Nonnull Result orig, @Nullable Result score); @Nonnull static ResultList newResultList(@Nonnull List<? extends Result> results); @SafeVarargs @Nonnull static ResultList newResultList(R... results); @Nonnull static BasicResultMap newResultMap(@Nonnull Iterable<? extends Result> results); @SafeVarargs @Nonnull static BasicResultMap newResultMap(R... results); static Collector<Result,?,ResultList> listCollector(); static Function<Result,BasicResult> basicCopyFunction(); static BasicResult fromEntry(Map.Entry<Long,Double> entry); static Function<Map.Entry<Long,Double>,Result> fromEntryFunction(); static Equivalence<Result> basicEquivalence(); static Ordering<Result> idOrder(); static Ordering<Result> scoreOrder(); static KeyExtractor<Result> keyExtractor();  }### Answer:
@Test public void testCollectEmpty() { ResultList list = Stream.<Result>empty() .collect(Results.listCollector()); assertThat(list, hasSize(0)); }