About Me

Hi, my name is Wim Deblauwe, a software developer specialized in Java, Spring, and JVM related tooling.

I wrote Taming Thymeleaf, a book to learn more about using Thymeleaf with Spring Boot. I also have a few open-source projects: one that makes it easy to do Spring Boot error handling, another for integration of Cypress with Testcontainers and a few others.

I blog regularly here about Spring Boot, Thymeleaf,Asciidoctor and other programming related subjects.

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Recent posts

Jun 15, 2019

Running Cypress tests with TestContainers for a Spring Boot with Thymeleaf application

UPDATE: The full test class code in this post does not actually fail the test when the Cypress tests fail. See my updated example at ./blog/2019/06/16/ensure-junit-test-fails-when-cypress-tests-fail/[Ensure JUnit test fails when Cypress tests fail]. At the last ng-be conference I saw a demo of Cypress. Cypress allows to do functional testing of your web application, quite similar to Selenium for example, but still quite different. Ever since that time, I wanted to try it out, but never got around to it until this week.


Feb 21, 2019

Announcing BIOB an binary object storage library

I am announcing a new open-source project I am working on: BIOB It is still very early days, but there is already a fully functional local file system implementation and an in-memory implementation for testing. See https://github.com/wimdeblauwe/biob for full details and a usage example on how to use the library in your own project. It does not depend on Spring or Spring Boot, but I have used it in that context so far because that is what I use for all of my projects.


Dec 24, 2018

Version 1.0.2 of Practical Guide to Building an API Back End with Spring Boot released

You can download an updated version of my book 'Practical Guide to Building an API Back End with Spring Boot' from InfoQ: https://www.infoq.com/minibooks/spring-boot-building-api-backend The changelog can be viewed at https://wimdeblauwe.wordpress.com/my-spring-boot-book/


Sep 26, 2018

Switching between JDK 8 and 11 using SDKMAN

I have written about switching JDK versions on your mac before. With JDK 11 now being out, it is time to give an updated version.


Sep 10, 2018

Spring Boot book published via Infoq

I am so happy because today my Spring Boot book is finally available! See https://www.infoq.com/minibooks/spring-boot-building-api-backend for all the details.


Aug 30, 2018

Tip on migration to Spring Boot 2 when using Flyway

Spring Boot 1.5.x uses Flyway 3 while Spring Boot 2.x uses Flyway 5. According to the official migration guide for Spring Boot 2, you need to do 2 releases to be able to migrate an application from Spring Boot 1 to Spring Boot 2 if you are using Flyway: First upgrade your 1.5.x Spring Boot application to Flyway 4 (4.2.0 at the time of writing), see the instructions for Maven and Gradle.


Jul 6, 2018

Datadog integration with AWS Elastic Beanstalk for Spring Boot application

If you have an application deployed on AWS Elastic Beanstalk and you want to add Datadog integration to it, then these instructions might help you out. I started out with the instructions at https://www.datadoghq.com/blog/deploy-datadog-aws-elastic-beanstalk/ but they use the older version 5 of the datadog-agent and not the newer version 6. In your source code, you normally have a .ebextensions folder to configure the Elastic Beanstalk deployment. Inside that folder, create the following files (Create directories as needed):


Jun 10, 2018

PageImpl JSON serialization with Spring Boot 2

During the migration of a Spring Boot application from 1.5.13 to 2.0.2, some of my Spring Rest Docs tests started failing. The reason being that some of my RestController s return a org.springframework.data.domain.PageImpl object (from Spring Data Commons). @RestController public class MyRestController { @GetMapping public PageImpl<SomeDtoObject> listAll() { ... } } With Spring Boot 1.5.13, this results in JSON like this: {"content":[{...},{...},....],"totalElements":50,"totalPages":3,"last":false,"size":20,"number":0,"numberOfElements":1,"first":true,"sort":[{"direction":"DESC","property":"date","ignoreCase":false,"nullHandling":"NATIVE","ascending":false,"descending":true}]} However, with Spring Boot 2.


Oct 8, 2017

Building an AsciidoctorJ extension to execute JavaScript

I love using Asciidoctor for writing documentation. I mainly got to know it through the excellent Spring REST Docs project. I wanted to build an extension (kind of a plug-in) for Asciidoctor. As I don’t know Ruby, writing an extension in Ruby was a bit too much. Luckily, there is AsciidoctorJ (The JVM version of Asciidoctor) which lets me write extensions in any JVM language. Here, we will be using plain Java, but Groovy for example would work equally well.


Sep 20, 2017

Using Spring Boot with JavaFX - Using Spring Profiles

In the previous post, I showed ./blog/2017/09/18/using-spring-boot-with-javafx/[how to get started with Spring Boot and JavaFX]. Continuing with the same example, we are going to create a new implementation of the CountryService interface that talks to the Open AQ Platform API so the list of countries will be a lot bigger than our HardcodedListCountryService we have now. Using Retrofit First, we add 2 dependencies in our pom.xml to be able to use Retrofit: