* Even if empty string, treated as empty plainly. So "IF pmb != null" is false if empty.
     * @param hostname The parameter value of hostname. (NotNull)
     */
    public void setHostname(String hostname) {
        registerVariable("hostname", hostname);
    }

    /**
     * Set the value of count, used in parameter comment. <br>

                    } else {
                        postcard.addTo(fessConfig.getMailFromAddress());
                        postcard.dryrun();
                    }
                    postcard.setHostname(systemHelper.getHostname());
                    postcard.setLevel(level);
                    postcard.setCount(String.valueOf(levelEvents.size()));

                    postcard.setDataIndexSize(getValueFromMap(dataMap, "dataIndexSize", "0"));
                    postcard.setDataIndexExecTime(getValueFromMap(dataMap, "dataIndexExecTime", "0"));
                    postcard.setHostname(getValueFromMap(dataMap, "hostname", StringUtil.EMPTY));
                    postcard.setWebFsCrawlEndTime(getValueFromMap(dataMap, "webFsCrawlEndTime", StringUtil.EMPTY));

            @Override
            public boolean isChangedClusterState(int status) {
                // State has changed
                return true;
            }

            @Override
            public String getHostname() {
                return "test-hostname";
            }
        };

        FessConfig fessConfig = createTestFessConfig();

        // Register components

        assertNotNull(systemHelper.getHostname());
        try {
            envMap.put("COMPUTERNAME", "xxx");
            assertEquals("xxx", systemHelper.getHostname());
        } finally {
            envMap.remove("COMPUTERNAME");
        }
        try {
            envMap.put("HOSTNAME", "yyy");
            assertEquals("yyy", systemHelper.getHostname());
        } finally {

            return;
        }

        try {
            final SearchEngineClient client = ComponentUtil.getSearchEngineClient();
            final String hostname = ComponentUtil.getSystemHelper().getHostname();
            final String indexName = resolveIndexName();

            ensureIndexExists(client, indexName);

            for (int i = 0; i < events.size(); i += BATCH_SIZE) {

    .build();

// Create a server certificate and a server that uses it.
HeldCertificate serverCertificate = new HeldCertificate.Builder()
    .commonName("ingen")
    .addSubjectAlternativeName(server.getHostName())
    .signedBy(rootCertificate)
    .build();
HandshakeCertificates serverCertificates = new HandshakeCertificates.Builder()
    .addTrustedCertificate(rootCertificate.certificate())

        final long now = System.currentTimeMillis();
        final long ttl = ComponentUtil.getFessConfig().getCoordinatorHeartbeatTtlAsInteger().longValue();
        final String hostname = ComponentUtil.getSystemHelper().getHostname();
        final String targetName = ComponentUtil.getFessConfig().getSchedulerTargetName();

        final String body = toJson(Map.of( //
                "type", TYPE_HEARTBEAT, //

        shutdownHookList.add(hook);
    }

    /**
     * Gets the hostname of the local machine.
     *
     * @return The hostname.
     */
    public String getHostname() {
        final Map<String, String> env = getEnvMap();
        if (env.containsKey("COMPUTERNAME")) {
            return env.get("COMPUTERNAME");
        }
        if (env.containsKey("HOSTNAME")) {

     */
    protected String getHostInfo() {
        final StringBuilder buf = new StringBuilder();
        try {
            final InetAddress ia = InetAddress.getLocalHost();
            final String hostname = ia.getHostName();
            if (StringUtil.isNotBlank(hostname)) {
                buf.append(hostname);
            }
            final String ip = IpAddressUtil.getUrlHost(ia);
            if (StringUtil.isNotBlank(ip)) {