This presentation by Andrii Rodionov (Senior Software Engineer, Consultant, GlobalLogic, Kyiv) was delivered at GlobalLogic Kharkiv Java Conference 2019 on June 9, 2019. Andrii listed drawbacks of the blocking approach and ways of improving performance of microservices by utilizing new features of Java 11, WebFlux, and WebClient. Video: https://youtu.be/6AQiwJj2Vk4

1. First Steps to Be Non-
Blocking in Web
Andrii Rodionov
@AndriiRodionov

2. About me
● Devoxx Ukraine
● Kotlin Night Kyiv
● JUG UA Leader

3. What we are developing?
User
Service
User
Amount
Service
Client
Service
“User”: “amount”
● How we usually communicate?
● RestTemplate
Microservices!

4. What we are developing?
User
Service
User
Amount
Service
Client
Service
“User”: “amount”
● How we usually communicate?
● RestTemplate
Microservices!
5 sec
5 sec
10 sec

5. Can we do faster?

6. What problems we have with this approach?

7. Blocking request processing!

8. We should be “reactive” and non-blocking!
instead of being blocked,
reacting to notifications as operations complete
or data becomes available

9. None-blocking request processing

10. To be non-blocking in Web
● Java 11
○ HttpClient#sendAsync(...)
● Project Reactor
○ Spring WebFlux
○ WebClient

11. To be Reactive or not to be?
● If your Spring MVC application works fine - don’t touch!
● Imperative programming is the easiest way to write,
understand, and debug code
● Reactive and non-blocking generally do not make
applications run faster

12. To be Reactive or not to be?
● Reactive in some cases (WebClient to execute remote calls
in parallel) can make applications faster
● On the whole, it requires more work and can increase
slightly the required processing time

13. To be Reactive or not to be?
The key benefit of reactive and non-blocking is:
● the ability to scale with a small,
● fixed number of threads
● and less memory

14. Thank you!
Questions?

15. JavaDay Odesa: Deep Dive
odesa.javaday.org.ua