In this presentation we discuss the latest trends in the Spring ecosystem as learned on Spring I/O Barcelona (the largest Spring Conference in Europe). Spring's growing reactive support (R2DBC & RSocket) in Spring Framework 5.2+. We stille see a lot of love between Sping & Kotlin with support for coroutines & Kofu and to conclude we discuss what's next in Spring Cloud development now that some of the Netflix projects are in maintenance mode.

1. Crafting integrated IT solutions that make your
business thrive.
Kristof Van Sever
@vanseverk
Wim Creuwels
@wimcreuwels
Jeroen Sterken
@jeroensterken
www.faros.be | hello@faros.be
Spring I/O Barcelona '19 Recap
Spring I/O Barcelona ‘19 Conference
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2. Cloud Native Enterprise
Development
• Software development / Projects
• IT Consultancy
• Audit/training
Technology focus
• Spring Ecosystem
• Pivotal CloudFoundry
Serverless
Reactive
Leuven (Belgium)
https://www.meetup.com/Spring-Framework-Belgium

3. https://www.meetup.com/Spring-Framework-Belgium
https://www.meetup.com/Reactive-Programming-Belgium/
https://www.meetup.com/Serverless-Belgium/

4. Introduction
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5. Introduction
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Community
Presentation
“Migrating a modern spring web application to serverless”
https://2019.springio.net/sessions/migrating-a-modern-spring-web-application-to-serverless

6. Server
Migrating a spring web application to serverless
Service
SpringDataJPA
SQL
db
MVC/Vaadin
internet
Infrastructure As Code
JSON Server
BaaS

7. Migrating a spring web application to serverless
S p r i n g C l o u d F u n c t i o n
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Bean
public Function<String, String> uppercase(String value) {
return value -> value.toUpperCase();
}
}
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-function-context</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-function-adapter-aws</artifactId>
</dependency>

8. Spring core 5.x
P a s t , p r e s e n t , f u t u r e
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9. Spring I/0 ‘19
• What’s coming, what’s coming after, and what will come one day?
• Reactive: Transaction support, R2DBC, Rsocket
• Platform & architecture: K8s, PCF, Spinnaker, Cloud Native with Spring: Spring
to Cloud X
• GraalVM, kotlin + coroutines, JVM
• Security & Spring
• Migrating a modern spring web application to serverless
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S u m m a r y

10. Spring 5.2
• GA 31 july
• Release notes
• Startup optimization
• Annotation processing (revisited)
• Reactive transaction support (tx operator)
• RSocket messaging
• Kotlin coroutines
• Webmvc.fn
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Spring boot 2.2

11. Spring 5.3
• Q2 2020
• Release notes
• Support JDK 13/14/15
• Code analysis annotation
• GraalVM native images
• Hibernate ORM 6
• Kotlin 1.4
• Jetty 10
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12. Beyond Spring 5.x
• JDK 11 baseline
• Revisiting java modules (ex. Java 9 modules)
• Jakarta EE alignment
• Project loom (fibers)
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Reactive support

14. Reactive support
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15. Reactive Transaction support && R2DBC
• Talk: Reactive Relational Database Connectivity (Ben Hale)
• Reactive journey continues…
• Finally support for @Transactional
• Becoming even more important since MongoDB 4.0 and R2DBC
• Imperative transactions -> ThreadLocal storage
• All happens on the same thread…
• Reactive transactions
• Can’t use ThreadLocal due to Reactive model but to SubscriberContext
• Can be non-blocking from the Java perspective
• Will still be occupying a database connection from the DB perspective
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16. Reactive Transaction support && R2DBC
• With R2DBC now reactive integration with SQL Database drivers
• Main focus is on a small service provider interface
• More user-focused interfaces can be built onto simple SPI
• Also support through Spring Data R2DBC
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@Repository
public interface CoffeeRepository extends ReactiveCrudRepository<Coffee, Long> {
@Query("SELECT id, name, score FROM coffee")
Flux<Coffee> findAll();
}

17. Reactive Transaction support && R2DBC
• Ongoing development
• Anyone interested in helping out? ->
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18. Reactive streams over JVMs through RSocket
• Talk: Multi-Service Reactive Streams Using Spring, Reactor, and Rsocket (Ben
Hale)
• “RSocket is a binary protocol for use on byte stream transports such as TCP,
WebSockets, and Aeron.”
• Different symmetric models via async message passing over a single
connection
• request/response (stream of 1)
• request/stream (finite stream of many)
• fire-and-forget (no response)
• channel (bi-directional streams)
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19. Reactive streams over JVMs through RSocket
• Basic interfaces available
• But also part of Spring messaging
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@Controller {
@MessageMapping("coffeeOrders")
public Flux<CoffeeOrder> coffeeOrdersStream(CoffeeServerSubscription request) {
return Flux.range(1, 1000).map(n -> randomCoffee()).delayElements(Duration.of(1,
SECONDS));
}
}
public Flux<CoffeeOrder> receiveCoffeeOrders() {
return this.requester
.route("coffeeOrders")
.data(new CoffeeServerSubscription("WaiterName"))
.retrieveFlux(CoffeeOrder.class);
}

20. Reactive streams over JVMs through RSocket
• RSocket Demo: https://github.com/vanseverk/coffeesocket
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21. Spring Cloud
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22. Cloud-Native with Spring
• Spring Cloud on Kubernetes
• Andreas Falk
• Configuration Management with Kubernetes, a Spring Boot use-case
• Nicolas Frankel
• Kubernetes and/or Cloud Foundry - How to run your Spring Boot Microservices
on state-of-the-art cloud platforms
• Matthias Haeussler
• Going Cloud Native with Spring Cloud Azure
• Julien Dubois / Josh Long
• Spring to Google Cloud Native
• Ray Tsang / Josh Long
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23. Post Spring-Cloud-Netflix
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24. Post Spring-Cloud-Netflix
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• Spring Cloud Netflix Eureka (client/server)
• Spring Cloud Netflix Ribbon
• Spring Cloud Netflix Zuul
• Spring Cloud Netflix Hystrix (stream, dashboard)
• Spring Cloud Netflix Turbine (stream)
• Spring Cloud Netflix Archaius

25. Post Spring-Cloud-Netflix
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• Spring Cloud Greenwich.RELEASE
• Spring Cloud Netflix Projects Entering Maintenance Mode
• Spring Cloud Netflix Ribbon
• Spring Cloud Netflix Zuul
• Spring Cloud Netflix Hystrix (stream, dashboard)
• Spring Cloud Netflix Turbine (stream)
• Spring Cloud Netflix Archaius

26. Post Spring-Cloud-Netflix
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• Spring Cloud Netflix replacements
CURRENT REPLACEMENT
Hystrix Resilience4j
Hystrix Dashboard / Turbine Micrometer + Monitoring System
Ribbon Spring Cloud Loadbalancer
Zuul 1 Spring Cloud Gateway
Archaius 1 Spring Boot external config + Spring
Cloud Config

27. Post Spring-Cloud-Netflix
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old stack new stack

28. Spinnaker
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29. Spinnaker
• Cutting-edge continuous Delivery: Automated Canary Analysis through
Spring-based Spinnaker (Andreas Evers)
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30. Spinnaker
• “Spinnaker is an open source, multi-cloud continuous delivery platform for
releasing software changes with high velocity and confidence.”
• Multi-cloud, including K8S, PAS, AWS EC2, Google Compute Engine, etc
• Includes overviews over different clouds
• Automated deployments through pipelines
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31. Spinnaker
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32. Spinnaker
• Offers Automated Canary Analysis
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33. Other
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34. 22/05/2019 34

35. Spring & Kotlin
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36. Spring & Kotlin
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T o d a y
Building web applications with Spring Boot & Kotlin
https://spring.io/guides/tutorials/spring-boot-kotlin/

37. Spring & Kotlin
• Kofu
• Different configuration model for Spring Boot
• Minimalist, efficient and explicit
• No auto-config based on classpath, developer is in control
• Configuration as code
• Leverages Spring Boot infrastructure using functional bean registration
• Allows to run as GraalVM native executables
• Kotlin native reactive flows
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N e x t s t e p s
https://github.com/spring-projects/spring-fu
Spring Fu is an incubator for features like Kofu configuration, Coroutines and
GraalVM native image support

38. Spring & Kotlin
• Kofu
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N e x t s t e p s

39. Spring & Kotlin
• Coroutines
• Lightweight threads allowing to write non-blocking code in an imperative way
• Since Kotlin 1.3
• Coroutines 1.2 introduces Flow Type
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N e x t s t e p s

40. Spring & Kotlin
• Reactive API
• Coroutines
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N e x t s t e p s
fun findOne(id: String): Mono<User>
suspend fun findOne(id: String): User?

41. Spring & Kotlin
Reactor
fun handler(): Mono<Void>
fun handler(): Mono<T>
fun handler(): Flux<T>
Coroutines
suspend fun handler()
suspend fun handler(): T
fun handler(): Flow<T>
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N e x t s t e p s

42. Spring & Kotlin
• Coroutines
• Going Reactive with Spring, Coroutines and Kotlin Flow
• https://spring.io/blog/2019/04/12/going-reactive-with-spring-coroutines-and-
kotlin-flow
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N e x t s t e p s

43. JVM
• GraalVM for Java developers
• Compiler on top of Java Hotspot
• Multilanguage support
• Included in OpenJDK
• Native images
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44. Resources
• Spring I/O 2019 - Keynote
by Juergen Hoeller, Ben Hale, Violeta Georgieva and Sébastien Deleuze
https://www.youtube.com/watch?v=Ylrxpbs6vcs
• https://2019.springio.net/sessions
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45. Contact
Gaston Geenslaan 11 B4
3000 Leuven
hello@faros.be
+32(0)16 240 840
@FarosBelgium farosbe

46. info@faros.be
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