@SuppressWarnings("unchecked")
	public static <E, T extends Collection<E>> T empty(Class<?> collectionClass) {
		if (null == collectionClass) {
			return (T) Collections.emptyList();
		}

		if (Set.class.isAssignableFrom(collectionClass)) {
			if (NavigableSet.class == collectionClass) {
				return (T) Collections.emptyNavigableSet();
			} else if (SortedSet.class == collectionClass) {
				return (T) Collections.emptySortedSet();
			} else {
				return (T) Collections.emptySet();
			}
		} else if (List.class.isAssignableFrom(collectionClass)) {
			return (T) Collections.emptyList();
		}

		// 不支持空集合的集合类型
		throw new IllegalArgumentException(StrUtil.format("[{}] is not support to get empty!", collectionClass));
	}
@Test
	public void emptyTest() {
		final SortedSet<String> emptySortedSet = CollUtil.empty(SortedSet.class);
		assertEquals(Collections.emptySortedSet(), emptySortedSet);

		final Set<String> emptySet = CollUtil.empty(Set.class);
		assertEquals(Collections.emptySet(), emptySet);

		final List<String> emptyList = CollUtil.empty(List.class);
		assertEquals(Collections.emptyList(), emptyList);
	}