How to do server support Multi-Threading and High concurrency

[CCint3]

AsyncHttpServer server = new AsyncHttpServer();

server.get("/", new HttpServerRequestCallback() { @Override public void onRequest(AsyncHttpServerRequest request, AsyncHttpServerResponse response) { Thread.currentThread().getId(); response.send("Hello!!!"); } }); server.listen(5000);

The above code is single threaded. How to support multi-threading and high concurrency?