### Question:
CollectionUtils { public static Set<String> removeBlankEntries(Set<String> originalSet) { if (isEmpty(originalSet)) { return originalSet; } Set<String> result = new HashSet<>(originalSet.size()); for (String entry : originalSet) { if (StringUtils.isNotBlank(entry)) { result.add(entry); } } return result; } private  CollectionUtils(); static Set<String> removeBlankEntries(Set<String> originalSet); static List<T> asList(T... values); static Set asCaseInsensitiveHashSet(Object... values); static Set<T> asSet(T... values); static LinkedHashSet<T> asOrderedSet(T... values); static Map<V, K> invertMap(final Map<K, V> map); static Map<K, M> transformMap(final Map<K, I> map,
                                                                        final Function<I, M, E> mapper); static List<M> transformList(final Collection<I> values,
                                                                    final Function<I, M, E> mapper); static Set<M> transformSet(final Collection<I> values,
                                                                  final Function<I, M, E> mapper); static T getFirstItem(final Collection<T> collection); static T getFirstItem(final Collection<T> collection, final T defaultValue); static boolean genericCompare(T valA, T valB); static boolean compareCaseInsensitiveMapOfSetOfStrings(Map<String, Set<String>> valA,
            Map<String, Set<String>> valB); static int createHashForCaseInsensitiveMapOfSetOfStrings(Map<String, Set<String>> map); static boolean isNotEmpty(final Collection<?> collection); static boolean isEmpty(Collection<?> collection); static Map<String, Set<String>> toAvPairMap(final Set<String> names, final String value); static boolean isEmpty(Map<?, ?> map); static boolean isNotEmpty(Map<?, ?> map); static boolean anyHaveEntries(Object... containers); static Map<K, V> sortMapByValue(Map<K, V> map);  }### Answer:
@Test public void removeBlankEntriesEmpty() { Set<String> original = Collections.EMPTY_SET; Set<String> result = CollectionUtils.removeBlankEntries(original); assertThat(result).isEqualTo(original); }
@Test public void removeBlankEntriesNull() { assertThat(CollectionUtils.removeBlankEntries(null)).isNull(); }
@Test public void removeBlankEntries() { Set<String> original = CollectionUtils.asSet("", "A", "B", "C", "", "D", " ", " E ", "F", ""); Set<String> expected = CollectionUtils.asSet("A", "B", "C", "D", " E ", "F"); Set<String> result = CollectionUtils.removeBlankEntries(original); assertThat(result).isEqualTo(expected); }