* @return An {@link InputStream} to read the resource represented by the URL.
     */
    public static InputStream openStream(final URL url) {
        assertArgumentNotNull("url", url);

        try {
            final URLConnection connection = url.openConnection();
            connection.setUseCaches(false);
            return connection.getInputStream();
        } catch (final IOException e) {

        assertEquals(result, fsClient.preprocessUri(value));
    }

    public void test_preprocessUri_null() {
        try {
            fsClient.preprocessUri(null);
            fail();
        } catch (final CrawlerSystemException e) {}
        try {
            fsClient.preprocessUri("");
            fail();
        } catch (final CrawlerSystemException e) {}
    }

    }

    public void test_init_withInvalidSSLCertificate() {
        // Create a temporary invalid certificate file
        File invalidCertFile = null;
        try {
            invalidCertFile = File.createTempFile("invalid_cert", ".crt");
            try (FileWriter writer = new FileWriter(invalidCertFile)) {
                writer.write("INVALID CERTIFICATE CONTENT");
            }

        // Write test data to file
        try (FileOutputStream fos = new FileOutputStream(testFile)) {
            fos.write(getTestContent().getBytes(StandardCharsets.UTF_8));
        }

        // Create a temporary project.properties file for SystemHelper
        File propFile = File.createTempFile("project", ".properties");
        propFile.deleteOnExit();
        try (FileOutputStream fos = new FileOutputStream(propFile)) {

     */
    protected void createMappingIfEmpty(final String index, final String type, final Client client) {
        final String actualIndex = index + "." + type.toLowerCase(Locale.ENGLISH);
        try {
            boolean empty;
            try {
                empty = client.admin()
                        .indices()
                        .prepareGetMappings(actualIndex)
                        .execute()

        request.setAttribute(Constants.SEARCH_LOG_ACCESS_TYPE, Constants.SEARCH_LOG_ACCESS_TYPE_JSON);
        final JsonRequestParams params = new JsonRequestParams(request, fessConfig);
        try {
            response.setContentType("application/x-ndjson; charset=UTF-8");
            final long count = searchHelper.scrollSearch(params, doc -> {
                buf.setLength(0);
                buf.append('{');

    protected InitialContextUtil() {
    }

    /**
     * Creates and returns an initial context.
     *
     * @return the initial context
     */
    public static InitialContext create() {
        try {
            return new InitialContext();
        } catch (final NamingException ex) {
            throw new NamingRuntimeException(ex);
        }
    }

    /**

     *
     * @param resultSet
     *            The result set
     */
    public static void close(final ResultSet resultSet) {
        if (resultSet == null) {
            return;
        }
        try {
            resultSet.close();
        } catch (final SQLException e) {
            logger.log(format("ECL0017", e.getMessage()), e);
        }
    }

    /**
     * Moves the result set to the next position.

     */
    public String encodeSimilarDocHash(final String hash) {
        if (hash != null && !hash.startsWith(SIMILAR_DOC_HASH_PREFIX)) {
            try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
                try (GZIPOutputStream gos = new GZIPOutputStream(baos)) {
                    gos.write(hash.getBytes(Constants.UTF_8));
                }

        return 30000; // 30 seconds
    }

    private List<NetworkInterface> getAvailableNetworkInterfaces() {
        try {
            List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            interfaces.removeIf(ni -> {
                try {
                    return ni.isLoopback() || !ni.isUp() || ni.isVirtual();
                } catch (Exception e) {