factory.newAddress(
        proxy = Proxy.NO_PROXY,
      )
    val routeSelector = newRouteSelector(address)
    assertThat(routeSelector.hasNext()).isTrue()
    dns[uriHost] = dns.allocate(2)
    val selection = routeSelector.next()
    assertRoute(selection.next(), address, Proxy.NO_PROXY, dns.lookup(uriHost, 0), uriPort)
    assertRoute(selection.next(), address, Proxy.NO_PROXY, dns.lookup(uriHost, 1), uriPort)

    assertThat(client.proxySelector)
      .isNotInstanceOf(NullProxySelector::class.java)
    client =
      OkHttpClient
        .Builder()
        .proxy(Proxy.NO_PROXY)
        .build()
    assertThat(client.proxy).isSameAs(Proxy.NO_PROXY)
    assertThat(client.proxySelector)
      .isInstanceOf(NullProxySelector::class.java)
    client =
      OkHttpClient
        .Builder()

   *
   * Note that the list of proxies is never null, but it may be a list containing
   * only [Proxy.NO_PROXY]. This comes up in several situations:
   *
   * * If neither a proxy nor proxy selector is configured.
   * * If the proxy is configured explicitly as [Proxy.NO_PROXY].
   * * If the proxy selector returns only [Proxy.NO_PROXY].
   * * If the proxy selector returns an empty list or null.
   *

    builder = builder.writeTimeout(Duration.ofSeconds(0L))
    builder = builder.pingInterval(0L, TimeUnit.SECONDS)
    builder = builder.pingInterval(Duration.ofSeconds(0L))
    builder = builder.proxy(Proxy.NO_PROXY)
    builder = builder.proxySelector(NullProxySelector)
    builder = builder.cookieJar(CookieJar.NO_COOKIES)
    builder = builder.cache(Cache(File("/cache/"), Integer.MAX_VALUE.toLong()))

    protected CurlRequest createCurlRequest(final String url) {
        final CurlRequest request = Curl.get(url);
        final Proxy proxy = ComponentUtil.getFessConfig().getHttpProxy();
        if (proxy != null && !Proxy.NO_PROXY.equals(proxy)) {
            request.proxy(proxy);
        }
        return request;
    }

    /**
     * Deletes an installed artifact.
     *
     * @param artifact the artifact to delete