https://jersey.java.net/documentation/latest/async.html

CompletionHandlerAsyncResource.java

package com.example.app;

import java.util.Random;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.container.AsyncResponse;
import javax.ws.rs.container.CompletionCallback;
import javax.ws.rs.container.Suspended;
import javax.ws.rs.core.Response;

@Path("/async_cc")
public class CompletionHandlerAsyncResource {
	
	private static int numberOfSuccessResponse = 0;
	private static int numberOfFailures = 0;

	@GET
	public void asyncGet(@Suspended AsyncResponse asyncResponse) {

		asyncResponse.register((CompletionCallback)(t) ->{
			if(t == null){
				numberOfSuccessResponse++;
			}else{
				numberOfFailures++;
			}
			System.out.println("Success: " + numberOfSuccessResponse + "/ Failure: " + numberOfFailures);
		});
		
		new Thread(() -> {
			try{
				randomException();
				int sleepMillis = sleep();				
				log("runnable thread end.");
				Response response = Response.ok("Success (" + sleepMillis + ")").build();
				asyncResponse.resume(response);
			}catch(RuntimeException e){
				asyncResponse.resume(e);
			}
		}).start();

		log("server thread end.");
	}

	private void randomException() {
		if(new Random().nextInt(2) % 2 == 0) throw new RuntimeException();		
	}

	private int sleep() {
		try {
			int millis = new Random().nextInt(5) * 1000;
			log("sleep :" + millis);
			Thread.sleep(millis);
			return millis;
		} catch (InterruptedException e) {
			throw new RuntimeException(e);
		}
	}

	private void log(String message) {
		System.out.println(message
				+ " / " + Thread.currentThread().getId()
				+ " / " + Thread.currentThread().getName());
	}

}