TreeMultiset<@Nullable String> ms = TreeMultiset.create(comparator);

    ms.add("b");
    ms.add(null);
    ms.add("a");
    ms.add("b");
    ms.add(null, 2);

    assertThat(ms).containsExactly(null, null, null, "a", "b", "b").inOrder();
    assertEquals(3, ms.count(null));

    SortedSet<@Nullable String> elementSet = ms.elementSet();
    assertThat(elementSet.first()).isNull();

        byte[] baseKey = new byte[16];
        new SecureRandom().nextBytes(baseKey);

        byte[] derived1 = keyManager.deriveKey(baseKey, "label1", null, 32);
        byte[] derived2 = keyManager.deriveKey(baseKey, "label2", null, 32);
        byte[] derived3 = keyManager.deriveKey(baseKey, "label1", new byte[] { 1, 2, 3 }, 32);

        assertEquals(32, derived1.length, "Derived key should have correct length");

    }

    @Test
    void acceptHandlesNullName() throws Exception {
        SmbFile dir = Mockito.mock(SmbFile.class);
        SmbFilenameFilter filter = (d, n) -> n != null && n.startsWith("a");
        assertFalse(filter.accept(dir, null));
    }

    @Test
    void acceptPropagatesException() {
        SmbFile dir = Mockito.mock(SmbFile.class);
        SmbFilenameFilter filter = (d, n) -> {

        System.clearProperty("fess.conf.path");
        if (tempDir != null) {
            deleteRecursively(tempDir.toFile());
        }
        super.tearDown(testInfo);
    }

    private void deleteRecursively(final File file) {
        if (file.isDirectory()) {
            final File[] children = file.listFiles();
            if (children != null) {
                for (final File child : children) {

      @Override
      public int hashCode() {
        return countMap.hashCode();
      }
    }

    /** We use a special form of unboxing that treats null as zero. */
    private static int unbox(@Nullable Integer i) {
      return (i == null) ? 0 : i;
    }
  }

            final Throwable cause = t.getCause();
            if (cause != null) {
                errorName = cause.getClass().getCanonicalName();
            } else {
                errorName = t.getClass().getCanonicalName();
            }
            final FailureUrl failureUrl = storeFailureUrl(crawlerContext, urlQueue, errorName, t);
            if (failureUrl != null) {
                failureUrlId = failureUrl.getId();
            }

        assertTrue(updateCheckManager.isUpdateRequired(a, remoteRepository));

        file.getParentFile().mkdirs();
        file.createNewFile();
        updateCheckManager.touch(a, remoteRepository, null);

        assertFalse(updateCheckManager.isUpdateRequired(a, remoteRepository));

        assertNull(
                updateCheckManager.readLastUpdated(touchFile, updateCheckManager.getRepositoryKey(remoteRepository)));

     *
     * @param transport transport instance
     * @return corresponding channel or null
     */
    public ChannelInfo getChannelForTransport(SmbTransport transport) {
        return channels.values().stream().filter(c -> c.getTransport() == transport).findFirst().orElse(null);
    }

    /**
     * Remove a channel
     *
     * @param channel channel to remove
     */

     */
    public static String createBulkLine(final String index, final String type, final SuggestItem item) {
        if (item == null || item.getId() == null || item.getText() == null) {
            throw new SuggesterException("Invalid SuggestItem: item, id, or text is null");
        }

        final Map<String, Object> firstLineMap = new HashMap<>();
        final Map<String, Object> firstLineInnerMap = new HashMap<>();

        final String url = ComponentUtil.getFessConfig().getForumLink();
        if (StringUtil.isBlank(url)) {
            return null;
        }
        String target = null;
        final Locale locale = ComponentUtil.getRequestManager().getUserLocale();
        if (locale != null) {
            final String lang = locale.getLanguage();
            if (ComponentUtil.getFessConfig().isOnlineHelpSupportedLang(lang)) {