JCON 2018, Düsseldorf: Talk by Mario-Leander Reimer (@LeanderReimer, Principal Software Architect at QAware) Abstract: With Java EE 8 finally released and the latest additions to MicroProfile it is about time we have a closer look at how to develop modern and lightweight microservices with the latest API improvements. This session is a comprehensive guide showing how to develop state-of-the-art microservices with the latest Java EE 8 APIs. We will start by giving an overview of Java EE 8 and the latest API additions and improvements. Then we will implement, build and package our first working Java EE 8 microservice. We will then dive into the details of implementing synchronous RESTful web services, and learn about the specifics of data binding and content marshalling using the JSON-B and JSON-P APIs. We will see how to leverage the power of using the asynchronous APIs on the server as well as the client-side, and how Server-Sent-Events (SSE) can be used for push communication. Finally, we will cover some advanced topics such as validation, security, resiliency, health checks and diagnosability.

1. Mario-Leander Reimer, QAware GmbH
mario-leander.reimer@qaware.de
Building Microservices
with Java EE 8 and Microprofile
Düsseldorf, 09. Oktober 2018

2. Mario-Leander Reimer
Principal Software Architect, QAware GmbH
Contact Details
Mail: mario-leander.reimer@qaware.de
Twitter: @LeanderReimer
Github: https://github.com/lreimer/
09.10.2018
2
Developer && Architect
20+ years of experience
#CloudNativeNerd
Open Source Enthusiast
Speaker && Author

3. Fork me on Github.
https://github.com/lreimer/building-javaee-microservices

4. 4
loosely coupled
stateless

5. 5
Components All Along the Software Lifecycle.
DESIGN
 Complexity unit
 Data integrity unit
 Coherent and cohesive
features unit
 Decoupled unit
RUN
 Release unit
 Deployment unit
 Runtime unit
(crash, slow-down, access)
 Scaling unit
n:1
BUILD
 Planning unit
 Team assignment unit
 Knowledge unit
 Development unit
 Integration unit
1:1

6. Essential Design Principles.
6
Design for Distribution: Containers; microservices; API driven development.
Design for Configuration: One image, multiple environments.
Design for Resiliency: Fault-tolerant and self-healing.
Design for Elasticity: Scales dynamically and reacts to stimuli.
Design for Delivery: Short roundtrips and automated provisioning.
Design for Performance: Responsive; concurrent; resource efficient.
Design for Automation: Automated Dev & Ops tasks.
Design for Diagnosability: Cluster-wide logs, metrics and traces.
Design for Security: Secure Endpoints, API-Gateways, E2E-Encryption

7. Microservice Blueprint with Java EE 8 and Microprofile
7

8. Overview of Java EE 8 APIs.
CDI
Extensions
Web
Fragments
BeanValidation2.0
CDI 2.0
Managed Beans 1.0
JCA 1.7
JPA 2.2
JMS
2.0
JSP 2.3
EL 3.0
EJB 3.2
Batch 1.0
JSF 2.3
Interceptors
1.2
Mail 1.6
Common
Annotations 1.3
JTA 1.2
JAX-WS
1.4
JAX-RS
2.1
Concurrency 1.0
JSON-P
1.1
JSON-B
1.0
WebSocket
1.1
JAPSIC 1.1 JACC 1.5
Security1.0
Servlet 4.0
JCache 1.0
8

9. Overview of Eclipse MicroProfile 2.0 APIs.
9see https://microprofile.io/presentations/

10. Cloud-ready runtimes suited for Java EE microservices.
10
… and many more.

11. @ApplicationPath("api")
public class JAXRSConfiguration extends Application {
}
@Path("hello")
public class HelloWorldResource {
@GET
@Produces(MediaType.APPLICATION_JSON)
public JsonObject helloWorld() {
String hostname = ofNullable(getenv("HOSTNAME")).orElse("localhost");
return Json.createObjectBuilder()
.add("message", "Cloud Native Application Development with Java EE.")
.add("hostname", hostname)
.build();
}
}
Our first JAX-RS application and REST endpoint.
11

12. // JSON Patch is a web standard format for describing changes in a JSON document.
// The JSON Patch media type is application/json-patch+json.
[ { "op": "replace", "path": "/0/aString", "value": "Patched JSON-P." } ]
JsonArray jsonArray = Json.createArrayBuilder()
.add(Json.createObjectBuilder()
.add("aString", "Hello Json-P.")
.add("aInteger", 42)
.add("aBoolean", false)
.add("aNullValue", JsonValue.NULL))
.build();
JsonPatch jsonPatch = Json.createPatchBuilder(jsonPatchArray).build();
jsonPatch.apply(jsonArray)
Use JSON-P for flexible parsing and processing.
12
Add: add a value into an object or array.
Remove: remove a value from an object or array.
Replace: replaces a value. Logically identical to
using remove and then add.
Copy: copy a value from one path to another by
adding the value at a specified to another location.
Move: moves a value from one place to another
by removing from one location and adding to
another.
Test: tests for equality at a certain path for a
certain value.

13. JsonbConfig jsonbConfig = new JsonbConfig()
.withDateFormat("dd.MM.yyyy", Locale.GERMANY)
.withFormatting(true)
.withPropertyNamingStrategy(PropertyNamingStrategy.LOWER_CASE_WITH_DASHES)
.withNullValues(true)
.withPropertyOrderStrategy(PropertyOrderStrategy.REVERSE);
Jsonb jsonb = JsonbBuilder.newBuilder().withConfig(jsonbConfig).build();
String jsonBody = jsonb.toJson(jsonPojo);
JsonbPojo jsonbPojo = jsonb.fromJson(jsonBody, JsonbPojo.class);
@JsonbNillable
public class JsonbPojo {
@JsonbProperty(value = "greeting", nillable = true) private String message;
@JsonbNumberFormat("#,##0.00") private Integer answerToEverything;
@JsonbTransient private Object ignored;
}
Use JSON-B for easy data binding.
13

14. Building RESTful Web Services with Java EE 8
M.-Leander Reimer, Packt Publishing
eBook or Video Discount Code: BRWSWJ50
Print Discount Code: BRWSWJ15

15. 09.10.2018
QAware 16

16. Mario-Leander Reimer
mario-leander.reimer@qaware.de
@LeanderReimer xing.com/companies/qawaregmbh
linkedin.com/company/qaware-gmbh slideshare.net/qaware
twitter.com/qaware
youtube.com/qawaregmbh
github.com/qaware