Go最重要的特性是：隐形异步

package main

import (
  "fmt"
  "log"
  "net/http"
)

func main() {
  http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
    fmt.Fprintln(w, "Goodbye, World!")
  })
  log.Fatal(http.ListenAndServe(":8080", nil))
}

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;

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

public class HelloWorld {

    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8080), 0);
        server.createContext("/", new MyHandler());
        server.setExecutor(null); // creates a default executor
        server.start();
    }

    static class MyHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange t) throws IOException {
            String response = "Goodbye, World!";
            t.sendResponseHeaders(200, response.length());
            OutputStream os = t.getResponseBody();
            os.write(response.getBytes());
            os.close();
        }
    }

}