All 15 Java Networking & HTTP Client questions
More in Java Networking & HTTP Client
How would you add custom HTTP headers (like an Authorization bearer token) to an outgoing request using HttpRequest.Builder? How would you make an asynchronous, non-blocking HTTP request using HttpClient's sendAsync() method, and how does the returned CompletableFuture integrate with the rest of an asynchronous pipeline? How would you configure HttpClient with custom timeouts, a proxy, and connection pooling behavior, and what's the difference between a connection timeout and a request/response timeout? How would you send a POST request with a JSON request body using HttpClient, and correctly parse a JSON response using a library like Jackson? What is the java.net.Socket and ServerSocket class pair, and how would you implement a basic TCP client-server communication using them at a lower level than HttpClient? How would you send URL-encoded form data (application/x-www-form-urlencoded) using HttpClient, as opposed to a JSON request body? How would you use InetAddress to perform DNS resolution (converting a hostname to an IP address) programmatically, and what's the difference between InetAddress.getByName() and getAllByName()? How does HttpClient handle automatic following of HTTP redirects (3xx responses), and how would you configure or disable this behavior? How would you implement a custom BodySubscriber or BodyHandler to stream a very large HTTP response body incrementally, rather than buffering the entire response into memory at once? How would you implement retry logic with exponential backoff for HTTP requests made via HttpClient, given the client doesn't provide built-in retry support natively?
Advertisement
Java › Java Networking & HTTP Client

What is the modern java.net.http.HttpClient (introduced in Java 11), and how does it improve on the older HttpURLConnection for making HTTP requests?

Beginner

Answer

HttpClient provides a modern, fluent, builder-based API for constructing and sending HTTP requests (supporting HTTP/1.1 and HTTP/2, synchronous and asynchronous execution, and built-in support for common needs like redirects and timeouts) -- it significantly improves on the older HttpURLConnection, which was notoriously awkward and error-prone to use correctly (a confusing, low-level API originally designed decades ago, requiring careful manual handling of connection setup, streams, and error codes), making HttpClient the clearly recommended choice for any new Java code needing to make HTTP requests without pulling in a third-party library like Apache HttpClient or OkHttp.
HttpClient client = HttpClient.newHttpClient();

HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create("https://api.example.com/users"))
    .header("Accept", "application/json")
    .GET()
    .build();

HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.statusCode());
System.out.println(response.body());
Real-world example A microservice calling an external REST API migrates from the older, awkward HttpURLConnection (requiring manual stream management and confusing connection state handling) to the modern HttpClient, immediately simplifying the code with its fluent builder API and built-in JSON-friendly string body handling.

Common follow-ups: Why did the JDK team decide to introduce an entirely new HTTP client rather than improving HttpURLConnection directly?;What third-party libraries (like Apache HttpClient or OkHttp) were commonly used to work around HttpURLConnection's limitations before Java 11?

RESTful Web APIs & Controllers;Serialization & Deserialization
All 15 Java Networking & HTTP Client questions