### Question:
UuidHashGroupExtractor implements GroupExtractor<T> { @Override public Integer apply(T t) { byte[] uuidBytes = extractUuidBytes(t); HashCode hash = hashFunction.hashBytes(uuidBytes); return Math.abs(hash.asInt() % modulus); } UuidHashGroupExtractor(int modulus); @Override Integer apply(T t);  }### Answer:
@Test public void uuidsAreAppropriatelyHashed() { UUID uuid1 = UUID.fromString("00000000-0000-0000-0000-000000000000"); UUID uuid2 = UUID.fromString("00000000-0000-0000-0000-000000000001"); GroupExtractor<UUID> groupExtractor = new TestUuidHashGroupExtractor(2); assertEquals(groupExtractor.apply(uuid1), groupExtractor.apply(uuid1)); assertNotEquals(groupExtractor.apply(uuid1), groupExtractor.apply(uuid2)); }