The following five steps are required to complete this recipe:

1. Let's first create a User POJO:

public class User {

    private Long id;
    private String name;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    
    public User(Long id, String name) {
        this.id = id;
        this.name = name;
    }
    
    @Override
    public String toString() {
        return "User{" + "id=" + id + ", 
        name=" + name + '}';
    }
}

2. Then, create a slow bean to return User:

public class UserBean {
    
    public User getUser(){
        try {
            TimeUnit.SECONDS.sleep(5);
            long id = new Date().getTime();
            return new User(id, "User " + id);
        } catch (InterruptedException ex) {
            long id = new Date().getTime();
            return new User(id, "Error " + id);
        }
    }
}

3. Now, create a Managed task so that we can monitor it:

@Stateless
public class AsyncTask implements Callable<User>, ManagedTaskListener {

    private final long instantiationMili = new Date().getTime();
    
    private static final Logger LOG = Logger.getAnonymousLogger();
    
    @Override
    public User call() throws Exception {
        return new UserBean().getUser();
    }

    @Override
    public void taskSubmitted(Future<?> future, 
    ManagedExecutorService mes, Object o) {
        long mili = new Date().getTime();
        LOG.log(Level.INFO, "taskSubmitted: {0} - 
        Miliseconds since instantiation: {1}",
        new Object[]{future, mili - instantiationMili});
    }

    @Override
    public void taskAborted(Future<?> future, 
    ManagedExecutorService mes, Object o, Throwable thrwbl) 
    {
        long mili = new Date().getTime();
        LOG.log(Level.INFO, "taskAborted: {0} - 
        Miliseconds since instantiation: {1}", 
        new Object[]{future, mili - instantiationMili});
    }

    @Override
    public void taskDone(Future<?> future, 
    ManagedExecutorService mes, Object o, 
    Throwable thrwbl) {
        long mili = new Date().getTime();
        LOG.log(Level.INFO, "taskDone: {0} -
        Miliseconds since instantiation: {1}", 
        new Object[]{future, mili - instantiationMili});
    }

    @Override
    public void taskStarting(Future<?> future, 
    ManagedExecutorService mes, Object o) {
        long mili = new Date().getTime();
        LOG.log(Level.INFO, "taskStarting: {0} - 
        Miliseconds since instantiation: {1}", 
        new Object[]{future, mili - instantiationMili});
    }

}

4. Finally, create a service endpoint to execute our task and return its results:

@Stateless
@Path("asyncService")
public class AsyncService {

    @Resource
    private ManagedExecutorService executor;

    @GET
    public void asyncService(@Suspended AsyncResponse response) {
        int i = 0;

        List<User> usersFound = new ArrayList<>();
        while (i < 4) {
            Future<User> result = executor.submit(new AsyncTask());

            while (!result.isDone()) {
                try {
                    TimeUnit.SECONDS.sleep(1);
                } catch (InterruptedException ex) {
                    System.err.println(ex.getMessage());
                }
            }

            try {
                usersFound.add(result.get());
            } catch (InterruptedException | ExecutionException ex) {
                System.err.println(ex.getMessage());
            }

            i++;
        }

        response.resume(Response.ok(usersFound).build());
    }

}

5. To try this code, simply deploy it to Eclipse GlassFish 5 and open the following URL:

http://localhost:8080/ch09-task-status/asyncService