This document introduces KumuluzEE, a Java microservices framework. It discusses how KumuluzEE can be used to build a microservices-based online store application. KumuluzEE allows developing microservices using standard Java EE APIs and packaging them into independent JAR files. It also supports automated configuration and deployment of microservices to containers and clouds. The document ends by discussing how existing Java EE applications can be migrated to microservices with KumuluzEE.

2. KUMULUZEE –
MICROSERVICES WITH JAVA
Tilen Faganel
Sunesis d.o.o.
Mail: tilen.faganel@sunesis.si
Github: @tfaga
Web: https://kumuluz.com
Matjaž B. Jurič
UL FRI
Mail: matjaz.juric@kumuluz.com
Web: https://kumuluz.com

3. Microservice architecture by example
Lets build an online store!

4. UIUI
CatalogueCatalogue
Cart & paymentCart & payment
DeliveryDelivery
Application server
WAR/EAR
DB
Queue

5. Monolith applications
Well-known
Easier to manage and deploy
Intimidating to developers
Scaling can be difficult
Continuous deployment can be difficult
…

6. UIUI
CatalogueCatalogue
Cart & paymentCart & payment
DeliveryDelivery
NoSQL DB
DB
Queue

7. UIUI
CatalogueCatalogue
Cart & paymentCart & payment
DeliveryDelivery
NoSQL DB
DB
Queue
CatalogueCatalogueCatalogueCatalogue
Cart & paymentCart & payment

8. Perfect for building new, modern, cloud-native Java applications

9. Use standard EE APIs
Completely modular
Easy migration of existing
applications
Automates configuration
Pack into independent JAR

10. Servlet + JAX-RS
+ JPA, CDI,
Bean Validation,
JSON-P
JAR size 1,5 MB 5 MB 15 MB

11. <dependency>
<groupId>com.kumuluz.ee</groupId>
<artifactId>kumuluzee-core</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>com.kumuluz.ee</groupId>
<artifactId>kumuluzee-servlet-jetty</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>com.kumuluz.ee</groupId>
<artifactId>kumuluzee-jax-rs-jersey</artifactId>
<version>2.0.0</version>
</dependency>
Add the required dependencies
(only the components or implementations,
that we want)
@Path("catalog")
public class SampleREST {
@GET
@Produces({"application/xml", "application/json"})
public Response hello() {
return Response.ok(“Hello from KumuluzEE”);
}
}
Use standard Java EE APIs
@ApplicationPath("rest")
public class RestApplication extends Application {
}

12. build
$ mvn clean package
run directly
$ java -cp target/classes:target/dependency/* com.kumuluz.ee.EeApplication
or run the created JAR
$ java -jar target/kumuluzee-example-1.0.0-SNAPSHOT.jar

13. …
Docker
First class support for Docker containers - for every cloud

14. Demo

15. Complexity of the system increases
Management of multiple databases
Transaction boundaries are smaller
More coordination is required
Drawbacks

16. How about existing Java EE applications?

17. How can we migrate the monoliths into microservices step-by-step?

18. Package, configure, deploy and scale

19. Tilen Faganel
Sunesis d.o.o.
Mail: tilen.faganel@sunesis.si
Github: @tfaga
Web: https://kumuluz.com
Matjaž B. Jurič
UL FRI
Mail:
matjaz.juric@kumuluz.com
Web: https://kumuluz.com