How to send requests through a proxy in Java (HttpClient)

import java.net.Authenticator;
import java.net.InetSocketAddress;
import java.net.PasswordAuthentication;
import java.net.ProxySelector;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class ProxyExample {
    private static final String HOST = "HOST";
    private static final String PORT = "PORT";
    private static final String LOGIN = "LOGIN";
    private static final String PASSWORD = "PASSWORD";

    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
            // Proxy over HTTP; for HTTPS sites the client opens the tunnel itself
            .proxy(ProxySelector.of(new InetSocketAddress(HOST, Integer.parseInt(PORT))))
            // We give the login and password only when the proxy asks for them
            .authenticator(new Authenticator() {
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    if (getRequestorType() == RequestorType.PROXY) {
                        return new PasswordAuthentication(LOGIN, PASSWORD.toCharArray());
                    }
                    return null;
                }
            })
            .connectTimeout(Duration.ofSeconds(15))
            .build();

        HttpRequest request = HttpRequest.newBuilder(URI.create("https://api.ipify.org"))
            .timeout(Duration.ofSeconds(30))
            .GET()
            .build();

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

        // The service returns the address the request came from
        System.out.println(response.body());
    }
}