Content associated with the talk OpenAPIs are everywhere given at EclipseCon Europe 2018 (video)


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This repository contains the examples and the code demo presented during the talk.

OpenAPI specification

The OpenAPI-Spec folder contains the OpenAPI specification for the Todo-Application.

Open it in Swagger-Editor online:

Postman collection

The postman collection can be found here: Postman/todoapp.postman_collection.json

You can get the same result if you import the todoapp.v2.yaml file into Postman.

Import feature in Postman

Server implementation

There are 2 server implementation based on Thorntail.

To start the application just run following command inside a project:

mvn thorntail:run

The server is started on port 8080.

If you start version with the OpenAPI support the generated spec is available at:


Client implementation

The OpenAPI-Generator jar is prepared in the todoapp_client folder.

How to generate the client:

java -jar ./openapi-generator-cli-3.3.1.jar generate -i ../OpenAPI-Spec/todoapp.yaml -g java -o out/

Import the project in the out/ in Eclipse IDE.

Edit TaskApiTest class, remove the @Ignore annotation and edit the fist test:

public void tasksCreateTest() throws ApiException {
    Task task = new Task();
    task.setDescription("Publish slides");
    Task response = api.tasksCreate(task);


Run it.



The OpenAPI Specification (formally known as Swagger) describes APIs in a way that is standardized, machine-readable, and programming language-agnostic. It is an open source project hosted by the Linux Foundation.

There have been many announcements regarding frameworks or tools supporting this standard: For example, Eclipse MicroProfile 1.3 provides a set of annotations that can be used on top of JAX-RS, and version 3.5.2 of Eclipse Vert.x provides automatic requests validation.

The standard is also well-adopted. Many products describe their API as an OpenAPI Specification: Docker, OpenShift, Microsoft Azure, to name a few. The government of Netherlands has adopted the OpenAPI Specification as a national standard.

This talk will provide an overview of the specification format, then it will present some implementation examples with different frameworks. Useful tools; such as an editor based on Eclipse Xtext and a code generator, will also be presented. The examples here are taken from real projects.

All of the tools presented in this talk are open-source.


The presentation was recorded and is availble on YouTube: OpenAPIs are everywhere | EclipseCon Europe 2018.

Get in touch

Use the issue tracker on GitHub.

You can also contact me on Twitter: @j2r2b


Code is under Eclipse Public License - v 2.0. Documentation and slides are under the Creative Commons BY-SA 4.0