Ahh, java. You never change, even if you're modern

    HttpClient client = HttpClient.newBuilder()
        .version(Version.HTTP_1_1)
        .followRedirects(Redirect.NORMAL)
        .connectTimeout(Duration.ofSeconds(20))
        .proxy(ProxySelector.of(
           new InetSocketAddress("proxy.example.com", 80)
        ))
        .authenticator(Authenticator.getDefault())
        .build();

       HttpResponse<String> response = client.send(request, BodyHandlers.ofString());

       System.out.println(response.statusCode());
       System.out.println(response.body());

For the record, you're most likely not even interacting with that API directly if you're using any current framework, because most just provide automagically generated clients and you only define the interface with some annotations