@SafeVarargs
	public static <T> Set<T> unionDistinct(Collection<T> coll1, Collection<T> coll2, Collection<T>... otherColls) {
		final Set<T> result;
		if (isEmpty(coll1)) {
			result = new LinkedHashSet<>();
		} else {
			result = new LinkedHashSet<>(coll1);
		}

		if (isNotEmpty(coll2)) {
			result.addAll(coll2);
		}

		if (ArrayUtil.isNotEmpty(otherColls)) {
			for (Collection<T> otherColl : otherColls) {
				if (isEmpty(otherColl)) {
					continue;
				}
				result.addAll(otherColl);
			}
		}

		return result;
	}
@SuppressWarnings("ConstantValue")
	@Test
	public void unionDistinctNullTest() {
		final List<String> list1 = new ArrayList<>();
		final List<String> list2 = null;
		final List<String> list3 = null;
		final Set<String> set = CollUtil.unionDistinct(list1, list2, list3);
		assertNotNull(set);
	}