try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testRemove_nullValueQueriesUnsupported() {
    try {

    verifyOccupiedMethodsInAnotherThread(monitor, false, false, 0);
    monitor.enter();
    try {
      verifyOccupiedMethodsInCurrentThread(monitor, true, true, 1);
      verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
      monitor.enter();
      try {
        verifyOccupiedMethodsInCurrentThread(monitor, true, true, 2);
        verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);

    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testRemove_nullValueQueriesUnsupported() {
    try {

    try {
      assertFalse(getMap().remove(null, v3()));
    } catch (NullPointerException tolerated) {
      // since the operation would be a no-op, the exception is not required
    }
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testRemove_nullValueQueriesUnsupported() {
    try {

    verifyOccupiedMethodsInAnotherThread(monitor, false, false, 0);
    monitor.enter();
    try {
      verifyOccupiedMethodsInCurrentThread(monitor, true, true, 1);
      verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);
      monitor.enter();
      try {
        verifyOccupiedMethodsInCurrentThread(monitor, true, true, 2);
        verifyOccupiedMethodsInAnotherThread(monitor, true, false, 0);

            throw new SmbException(unc + " UNC must end with '\\'");
        }

        final SmbTreeHandleImpl th = getTreeHandle();
        this.response = new Trans2FindFirst2Response(th.getConfig());

        try {
            th.send(new Trans2FindFirst2(th.getConfig(), unc, this.getWildcard(), this.getSearchAttributes(), th.getConfig().getListCount(),
                    th.getConfig().getListSize() - FIND_OVERHEAD), this.response);

            throw new CIFSException("Singleton context is already initialized");
        }
        final Properties p = new Properties();
        try {
            final String filename = System.getProperty("jcifs.properties");
            if (filename != null && filename.length() > 1) {

                try (FileInputStream in = new FileInputStream(filename)) {
                    p.load(in);
                }
            }

    public static String getDomainByName(String name) throws UnknownHostException {
        DirContext context;
        UnknownHostException uhe = null;

        try {
            context = new InitialDirContext();
            for ( ;; ) {
                try {
                    Attributes attributes = context.getAttributes(
                        "dns:/_ldap._tcp.dc._msdcs." + name,
                        new String[] { "SRV" }

     *
     * @return an Unsafe instance if successful
     */
    private static Unsafe getUnsafe() {
      try {
        return Unsafe.getUnsafe();
      } catch (SecurityException tryReflectionInstead) {
        // We'll try reflection instead.
      }
      try {
        return AccessController.doPrivileged(
            (PrivilegedExceptionAction<Unsafe>)
                () -> {

        crawlerContext.sessionId = sdf.format(new Date());
    }

    /**
     * Adds a URL to the crawling queue.
     * @param url The URL to add.
     */
    public void addUrl(final String url) {
        try {
            urlQueueService.add(crawlerContext.sessionId, url);
        } catch (final Exception e) {
            logger.warn("Failed to add url: " + url, e);
        }
        urlFilter.processUrl(url);
    }