### Question:
CollectionUtils { public static boolean isNotEmpty(final Collection<?> collection) { return !isEmpty(collection); }  static boolean isEmpty(final Collection<?> collection); static boolean isNotEmpty(final Collection<?> collection); static Map<K, List<V>> groupingBy(final Collection<V> collection, Function<? super V, ? extends K> keyMapper); static PairMap<L, R, List<V>> groupingBy(final Collection<V> collection, Function<? super V, ? extends L> leftMapper, Function<? super V, ? extends R> rightMapper); static Optional<V> matching(final Collection<V> collection, Function<V, ? extends Long> keyMapper, long value); static Optional<V> matching(final Collection<V> collection, Function<V, ? extends Integer> keyMapper, int value); static int sumByInt(Collection<Integer> collection); static long sumByLong(Collection<Long> collection);  }### Answer:
@Test public void testIsNotEmpty() { assertTrue(CollectionUtils.isNotEmpty(list)); }