1. First, we create a User POJO:

public class User implements Serializable{

    private Long id;
    private String name;
    
    public User(long id, String name){
        this.id = id;
        this.name = 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;
    }
    
}

2. Here, we define UserBean, which will act as a remote endpoint:

@Stateless
@Path("remoteUser")
public class UserBean {

    @GET
    public Response remoteUser() {
        long id = new Date().getTime();
        try {
            TimeUnit.SECONDS.sleep(5);
            return Response.ok(new User(id, "User " + id))
            .build();
        } catch (InterruptedException ex) {
            System.err.println(ex.getMessage());
            return Response.ok(new User(id, "Error " + id))
            .build();
        }
    }

}

3. Then finally, we define a local endpoint that will consume the remote one:

@Stateless
@Path("asyncService")
public class AsyncService {
    
    private Client client;
    private WebTarget target;

    @PostConstruct
    public void init() {
        client = ClientBuilder.newBuilder()
                .readTimeout(10, TimeUnit.SECONDS)
                .connectTimeout(10, TimeUnit.SECONDS)
                .build();
        target = client.target("http://localhost:8080/
        ch10-async-jaxrs/remoteUser");
    }

    @PreDestroy
    public void destroy(){
        client.close();
    }
    
    @GET
    public void asyncService(@Suspended AsyncResponse response){
        target.request().async().get(new 
        InvocationCallback<Response>() {
            @Override
            public void completed(Response rspns) {
                response.resume(rspns);
            }

            @Override
            public void failed(Throwable thrwbl) {
                response.resume(Response.status(Response.Status.
                INTERNAL_SERVER_ERROR).entity(thrwbl.getMessage())
                .build());
            }
        });
                
    }
    
}