Feature	RestTemplate	Java 11+ HttpClient
Threading	Blocking/synchronous	Supports both blocking and non-blocking async via sendAsync()
HTTP/2	HTTP/1.1 only	Native HTTP/2 support for better performance
API Design	Verbose, limited builder patterns	Fluent builder, clean separation of request and response
Dependency Footprint	Requires Spring context	Built-in to JDK—no external dependencies
Control	Higher-level convenience methods	Low-level: full control over headers, connection, etc.

public class HttpClientTest {
public void makeHttpRequests() {


// Blocks the calling thread;  (Blocking, Synchronous)
        // Uses HTTP/1.1

RestTemplate rt = new RestTemplate();
String body = rt.getForObject("https://api.example.com", String.class);
System.out.println(body);


// Java 11 HttpClient (Async, Non-blocking)
        // Uses HTTP/2

HttpClient client = HttpClient.newHttpClient();

HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com"))
                .build();

client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
                .thenApply(HttpResponse::body)
                .thenAccept(System.out::println);
    }
}