if (StringUtil.isNotBlank(getHttpProxyUsername())) {
                    Authenticator.setDefault(new Authenticator() {
                        @Override
                        protected PasswordAuthentication getPasswordAuthentication() {
                            return new PasswordAuthentication(getHttpProxyUsername(), getHttpProxyPassword().toCharArray());
                        }

            paramMap.put(Param.Client.PROXY_HOST, proxyHost);
            paramMap.put(Param.Client.PROXY_PORT, proxyPort);
            final String proxyUsername = fessConfig.getHttpProxyUsername();
            final String proxyPassword = fessConfig.getHttpProxyPassword();
            if (proxyUsername != null && proxyPassword != null) {

     * The value is, e.g.  <br>
     * comment: Username for HTTP proxy authentication.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getHttpProxyUsername();

    /**
     * Get the value for the key 'http.proxy.username' as {@link Integer}. <br>
     * The value is, e.g.  <br>
     * comment: Username for HTTP proxy authentication.