This is the demo for https://openjdk.org/jeps/8337789, it requires that current Java is https://github.com/openjdk/jdk-sandbox/tree/parttimenerd_jfr_cpu_time_sampler4

HttpRequestsExample.java

import java.io.IOException;
import java.net.*;

import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpExchange;

class HttpRequestsExample {

    private static HttpServer server;

    public static void main(String[] args) throws Exception {
        if (args.length != 1) {
            System.err.println("Usage: java HttpRequestsExample <server|client>");
            System.exit(1);
        }

        if ("server".equalsIgnoreCase(args[0])) {
            startServer();
        } else if ("client".equalsIgnoreCase(args[0])) {
            runClient();
        } else {
            System.err.println("Invalid argument. Use 'server' or 'client'.");
            System.exit(1);
        }
    }

    // Method to start the HTTP server
    private static void startServer() throws IOException {
        server = HttpServer.create(new InetSocketAddress(8080), 0);
        server.createContext("/fast", new DelayHandler(100)); // 100ms delay
        server.createContext("/slow", new DelayHandler(1000)); // 1000ms delay
        server.setExecutor(null); // creates a default executor
        server.start();
        System.out.println("Server started on port 8080");
    }

    // Method to run the client requests
    private static void runClient() throws InterruptedException {
        // Thread 1: Runs tenFastRequests
        Thread thread1 = new Thread(HttpRequestsExample::tenFastRequests);
        // Thread 2: Runs oneSlowRequest
        Thread thread2 = new Thread(HttpRequestsExample::oneSlowRequest);

        // Start both threads
        thread1.start();
        thread1.join();
        thread2.start();
        thread2.join();

        System.out.println("All requests completed.");
    }

    // Method to make ten fast requests
    private static void tenFastRequests() {
        for (int i = 0; i < 10; i++) {
            makeRequest("http://localhost:8080/fast"); // Local server endpoint
        }
    }

    // Method to make one slow request
    private static void oneSlowRequest() {
        makeRequest("http://localhost:8080/slow"); // Local server endpoint
    }

    // Helper method to make an HTTP request using HttpURLConnection
    private static void makeRequest(String urlString) {
        HttpURLConnection connection = null;
        try {
            URL url = new URI(urlString).toURL();
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            connection.getResponseCode();
        } catch (IOException e) {
            System.err.println("Request to " + urlString + " failed: " + e.getMessage());
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
        }
    }

    // Unified handler for both /fast and /slow endpoints
    static class DelayHandler implements HttpHandler {
        private final int delay;

        public DelayHandler(int delay) {
            this.delay = delay;
        }

        @Override
        public void handle(HttpExchange exchange) throws IOException {
            try {
                Thread.sleep(delay); // Simulate processing time based on delay
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
            exchange.sendResponseHeaders(200, 0);
            exchange.close();
        }
    }
}