public final static void main(final String[] args) throws Exception {

        // Create HTTP/1.1 protocol configuration
        final Http1Config h1Config = Http1Config.custom()
                .setMaxHeaderCount(200)
                .setMaxLineLength(2000)
                .build();

        // Use custom message parser / writer to customize the way HTTP
        // messages are parsed from and written out to the data stream.
        final HttpMessageParserFactory<ClassicHttpResponse> responseParserFactory = new DefaultHttpResponseParserFactory() {

            @Override
            public HttpMessageParser<ClassicHttpResponse> create() {
                final LineParser lineParser = new BasicLineParser() {

                    @Override
                    public Header parseHeader(final CharArrayBuffer buffer) {
                        try {
                            return super.parseHeader(buffer);
                        } catch (final ParseException ex) {
                            return new BasicHeader(buffer.toString(), null);
                        }
                    }

                };
                return new DefaultHttpResponseParser(h1Config, lineParser, DefaultClassicHttpResponseFactory.INSTANCE);
            }

        };
        final HttpMessageWriterFactory<ClassicHttpRequest> requestWriterFactory = new DefaultHttpRequestWriterFactory();

        // Create char coding configuration
        final CharCodingConfig charCodingConfig = CharCodingConfig.custom()
                .setMalformedInputAction(CodingErrorAction.IGNORE)
                .setUnmappableInputAction(CodingErrorAction.IGNORE)
                .setCharset(StandardCharsets.UTF_8)
                .build();

        // Use a custom connection factory to customize the process of
        // initialization of outgoing HTTP connections. Beside standard connection
        // configuration parameters HTTP connection factory can define message
        // parser / writer routines to be employed by individual connections.
        final HttpConnectionFactory<ManagedHttpClientConnection> connFactory = new ManagedHttpClientConnectionFactory(
                h1Config, charCodingConfig, requestWriterFactory, responseParserFactory);

        // Client HTTP connection objects when fully initialized can be bound to
        // an arbitrary network socket. The process of network socket initialization,
        // its connection to a remote address and binding to a local one is controlled
        // by a connection socket factory.

        // SSL context for secure connections can be created either based on
        // system or application specific properties.
        final SSLContext sslContext = SSLContexts.createSystemDefault();

        // Create a registry of custom connection socket factories for supported
        // protocol schemes.
        final TlsSocketStrategy tlsStrategy = new DefaultClientTlsStrategy(sslContext);

        // Use custom DNS resolver to override the system DNS resolution.
        final DnsResolver dnsResolver = new SystemDefaultDnsResolver() {

            @Override
            public InetAddress[] resolve(final String host) throws UnknownHostException {
                if (host.equalsIgnoreCase("myhost")) {
                    return new InetAddress[] { InetAddress.getByAddress(new byte[] {127, 0, 0, 1}) };
                }
                return super.resolve(host);
            }

        };

        // Create a connection manager with custom configuration.
        final PoolingHttpClientConnectionManager connManager = PoolingHttpClientConnectionManagerBuilder.create()
                .setTlsSocketStrategy(tlsStrategy)
                .setConnectionFactory(connFactory)
                .setDnsResolver(dnsResolver)
                .setPoolConcurrencyPolicy(PoolConcurrencyPolicy.STRICT)
                .setConnPoolPolicy(PoolReusePolicy.LIFO)
                .build();

        // Configure the connection manager to use socket configuration either
        // by default or for a specific host.
        connManager.setDefaultSocketConfig(SocketConfig.custom()
                .setTcpNoDelay(true)
                .build());
        // Validate connections after 10 sec of inactivity
        connManager.setDefaultConnectionConfig(ConnectionConfig.custom()
                .setConnectTimeout(Timeout.ofSeconds(30))
                .setSocketTimeout(Timeout.ofSeconds(30))
                .setValidateAfterInactivity(TimeValue.ofSeconds(10))
                .setTimeToLive(TimeValue.ofHours(1))
                .build());

        // Use TLS v1.3 only
        connManager.setDefaultTlsConfig(TlsConfig.custom()
                .setHandshakeTimeout(Timeout.ofSeconds(30))
                .setSupportedProtocols(TLS.V_1_3)
                .build());

        // Configure total max or per route limits for persistent connections
        // that can be kept in the pool or leased by the connection manager.
        connManager.setMaxTotal(100);
        connManager.setDefaultMaxPerRoute(10);
        connManager.setMaxPerRoute(new HttpRoute(new HttpHost("somehost", 80)), 20);

        // Use custom cookie store if necessary.
        final CookieStore cookieStore = new BasicCookieStore();
        // Use custom credentials provider if necessary.
        final CredentialsProvider credentialsProvider = CredentialsProviderBuilder.create()
                .build();
        // Create global request configuration
        final RequestConfig defaultRequestConfig = RequestConfig.custom()
            .setCookieSpec(StandardCookieSpec.STRICT)
            .setExpectContinueEnabled(true)
            .setTargetPreferredAuthSchemes(Arrays.asList(StandardAuthScheme.DIGEST))
            .setProxyPreferredAuthSchemes(Collections.singletonList(StandardAuthScheme.BASIC))
            .build();

        // Create an HttpClient with the given custom dependencies and configuration.

        try (final CloseableHttpClient httpclient = HttpClients.custom()
                .setConnectionManager(connManager)
                .setDefaultCookieStore(cookieStore)
                .setDefaultCredentialsProvider(credentialsProvider)
                .setProxy(new HttpHost("myproxy", 8080))
                .setDefaultRequestConfig(defaultRequestConfig)
                .build()) {
            final HttpGet httpget = new HttpGet("http://httpbin.org/get");
            // Request configuration can be overridden at the request level.
            // They will take precedence over the one set at the client level.
            final RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig)
                    .setConnectionRequestTimeout(Timeout.ofSeconds(5))
                    .build();
            httpget.setConfig(requestConfig);

            // Execution context can be customized locally.
            // Contextual attributes set the local context level will take
            // precedence over those set at the client level.
            final HttpClientContext context = ContextBuilder.create()
                    .useCookieStore(cookieStore)
                    .useCredentialsProvider(credentialsProvider)
                    .build();

            System.out.println("Executing request " + httpget.getMethod() + " " + httpget.getUri());
            httpclient.execute(httpget, context, response -> {
                System.out.println("----------------------------------------");
                System.out.println(httpget + "->" + new StatusLine(response));
                EntityUtils.consume(response.getEntity());
                return null;
            });
            // Last executed request
            context.getRequest();
            // Execution route
            context.getHttpRoute();
            // Auth exchanges
            context.getAuthExchanges();
            // Cookie origin
            context.getCookieOrigin();
            // Cookie spec used
            context.getCookieSpec();
            // User security token
            context.getUserToken();
        }
    }
This example demonstrates how to customize and configure the most common aspects
of HTTP request execution and connection management.
httpclient5/src/test/java/org/apache/hc/client5/http/examples/ClientConfiguration.java