This document discusses lightweight Java EE and the future of the platform. It provides an overview of Java EE 8 features like JAX-RS 2.1 and JSON-B 1.1. It also demonstrates Payara Micro, a lightweight Java EE runtime, and shows how to build a microservices application with stock tickers that publishes events and uses reactive clients. Finally, it explores the potential for Eclipse MicroProfile and configuration properties to further reduce overhead in the future.

1. Cloud-ready Micro Java EE 8
Ondro Mihályi | Payara Engineer
| @omihalyi
| @Payara_Fish

2. Who am I?
• Payara Engineer
• Java EE developer and lecturer
• Conference speaker
• Czech JUG leader
• Member of JCP and Eclipse foundation
• @omihalyi

3. What’s this all about?
• How lightweight is Java EE, really?
• What’s in Java EE 8 today?
• What could be in Java EE EE4J ??? in the future?

4. A little (recent) history...
• 12 June 2013: Java EE 7 Released
•Docker was 3 months old
•WildFly was still JBoss AS (and no Swarm)
•Before Spring Boot
•WebSphere Liberty Profile recently released

5. A little (recent) history...
• 21 September 2017: Java EE 8 Released, 4 years later
•Docker is now the dominant container format
•WildFly have fully product-ised WildFly Swarm
•Spring Boot have been making JARs not WARs for a few years
•IBM released Open Liberty
•Payara entered the fray and released Payara Micro
•Eclipse MicroProfile is established and progressing

6. What’s in Java EE 8?
• Upgrades
•JAX-RS 2.1
•Servlet 4.0
•Bean Validation 2.0
•JSF 2.3
•CDI 2.0
•JSON-P 1.1
• New
•Java EE Security
•JSON-B

7. What is Payara Micro?
• Payara Micro is…
•Micro! (~60MB disk size, ~30 MB RAM)
•Dynamically scalable
•Fully embeddable (if you want…)
•Web Profile “plus”
•On Maven Central
<dependency>
<groupId>fish.payara.api</groupId>
<ArtifactId>payara-api</artifactId>
<version>5.0.0-Alpha3</version>
<type>jar</type>
</dependency>

8. What is Payara Micro?
• Key APIs
• Servlets, JSTL, EL, JSP
• WebSockets
• JSF
• JAX-RS
• EJB Lite
• JTA
• JPA
• JCA (pluggable JMS)
• Bean Validation
• CDI
• Interceptors
• JBatch
• Concurrency
• JCache
• Config
• SOAP, remote EJB

9. Demo

10. Demo Scenario
• Stock! Micro Stock!
• Publish StockTicker events
• Listen on different endpoints

11. Demo Scenario
StockTickerStockTickerStockTicker
Produces Events
StockWeb
Consumes Events
Websocket Push

12. Demo 1
Creating the Stock Ticker
• What do we need?
• Stock object
• Stock Ticker to set the stock price
• Publisher for CDI event bus

13. Demo 2
Creating the Stock Web listener
• What do we need?
• Websocket endpoint
• Class to manage Websocket sessions
• Class to listen for Stock events on the CDI event bus
• Both these responsibilities can be in the same class

14. Integrating Java EE 8 Features

15. Demo
Making our MicroService generic
• What do we need to change?
• Non-Payara services can’t listen on the CDI event bus
• Solution: REST Server Sent Events (from JAX-RS 2.1)
• External services may not have access to a Stock object (or interface)
• Solution: Serialise our Stock object as JSON using JSON-B 1.0

16. private JsonObject toJson() {
JsonObjectBuilder objectBuilder = Json.createObjectBuilder()
.add("symbol", symbol)
.add("description", description)
.add("price", price);
return objectBuilder.build();
}
@Override
public String toString() {
return this.toJson().toString();
}
Demo 3 JSON-P manual toJson() method

17. @JsonbNillable
public class Stock implements Serializable {
private String symbol;
@JsonbTransient
private String description;
@JsonbProperty("RandomPrice")
private double price;
@Override
public String toString() {
JsonbConfig nillableConfig = new JsonbConfig().withNullValues(true);
return JsonbBuilder.create(nillableConfig).toJson(this);
}
}
private void observe() {
source.register((sseEvent)
-> {
this.stock = JsonbBuilder.create().fromJson(sseEvent.readData(), Stock.class);
});
source.open();
}
Demo 3 JSON-B serialisation and deserialisation
Learn more:
http://json-b.net

18. private void reactiveClient() {
CompletionStage<Response> cs1 = ClientBuilder.newClient()
.target("http://localhost:8080/jax-rs-2-1/books")
.request()
.rx()
.get();
CompletionStage<Response> cs2 = ClientBuilder.newClient()
.target("http://localhost:8080/jax-rs-2-1/magazines")
.request()
.rx()
.get();
cs1.thenCombine(cs2, (r1, r2) ->
r1.readEntity(String.class) + r2.readEntity(String.class))
.thenAccept(System.out::println);
}
Source: https://www.ibm.com/developerworks/library/j-whats-new-in-javaee-8/index.html
Author: Alex Theedom
Demo 4 JAX-RS reactive client API

19. Demo 4 SSE server endpoint in JAX-RS
@GET
@Produces(MediaType.SERVER_SENT_EVENTS)
public void eventOutput(@Context SseEventSink eventSink){
// send a single event
eventSink.send(sse.newEvent(stockTicker.getStock().toString()));
// registers the requester as a consumer of events
sseBroadcaster.register(eventSink);
}
@POST
@Path("broadcast")
@Consumes(MediaType.MULTIPART_FORM_DATA)
public void broadcast(@FormParam("event") String event){
// broadcasts the event to all registered consumers
sseBroadcaster.broadcast(sse.newEvent(event));
}

20. Demo 4
StockTickerStockTickerStockTicker
StockWeb
JAX-RS SSE
Client
Javascript SSE Client

21. The Future of Java EE…?

22. Demo 5
Integrating MicroProfile 1.1
<dependency>
<groupId>
org.eclipse.microprofile
</groupId>
<artifactId>
Microprofile-bom
</artifactId>
<version>1.1.0</version>
<type>pom</type>
<scope>provided</scope>
</dependency>
@Inject
@ConfigProperty(name = "stockticker.url")
private String stockTickerURL;
@Inject
@ConfigProperty(name = "stockticker.url")
private Instance<String> tickerURLConfig;
...
String url = tickerURLConfig.get()

23. Demo 5
Integrating MicroProfile
// Set system property
java -jar -Dstockticker.url=http://localhost:8081/StockTicker-1.0-SNAPSHOT/rest/sse StockWeb/target/StockWeb-
1.0-SNAPSHOT-microbundle.jar
// Use asadmin to set property in Hazelcast cluster
asadmin> set-config-property
--propertyName=stockticker.url
--propertyValue=http://localhost:8080/StockTicker-1.0-SNAPSHOT/rest/sse
--source=cluster
// Use asadmin to set property for specific instances in Hazelcast cluster
asadmin> send-asadmin-command
--targets=‘*‘
--command=set-config-property
--
--propertyName=stockticker.url
--propertyValue=http://localhost:8080/StockTicker-1.0-SNAPSHOT/rest/sse
--source=config
--sourceName=sever-config

24. Recap
•Java EE is incredibly adaptable to changing needs
• Recent change has been driven by vendors’ implementations
• Eclipse MicroProfile offers interesting ideas for the future

25. Thank you!