Have you ever wondered why IntelliJ can't resolve properties in your application.properties or application.yml? Short answer: you'll need an annotation processor in your classpath.

Integrating external services into an application is often challenging. Instead of doing the testing manually, the setup could be tested also automated. In case you are using Spring Boot, for a couple of services there exist an integration. This blog post will show how you can setup your Kafka tests to use an embedded Kafka server.

Storing dates in databases was traditionally done with java.sql.Date and java.sql.Timestamp. Since we would like to write modern applications, with Java 8 or 11, it is preferable to use an OffsetDateTime or a LocalDateTime. Spring Data JPA, for example, is mapping those fields automatically to the correct database field. There are still some challenges in combination with PostgreSQL.

One of the goals I set for this year is to explore Machine Learning (ML), so after having done a couple of courses here and there, I decided to do a -rather simple- starting project, where I could deal with some of the basic stages of the ML: Get the data, prepare it, choose a model, train it, evaluate it, export it, and make the predictions available for use. For this first project, I chose:

In March 2018 Java 10 was released. But a lot of projects haven't adopted even Java 9. I hope this article will help you figure out whether you should try recent releases or stay with current.