One of the earliest and most fundamental principle one learns while coding is programming by interface. Definition Interface-based programming defines the application as a collection of components, in which Application Programming Interface (API) calls between components may only be made through abstract interfaces, not concrete classes. Instances of classes will generally be obtained through other interfaces using techniques such as the Factory pattern. — Wikipedia https://en.

Last week, I wrote on how to migrate an existing Spring Boot application with a functional approach toward configuration. Since then, I got interesting feedback, and I had a presentation on that subject at Rockstar Night in Kiev, which made me think further. Here’s how I would refine my previous code.

As software developers, we behave like children. When we see shiny new things, we just have to play with them. That’s normal, accepted, and in general, even beneficial to our job…​ up to a point. When Java started to provide annotations with version 5, there was a huge move toward using them. Anywhere. Everywhere. Even when it was not a good idea to. But it was new, hence it had to be good. Of course, when something is abused, there’s a strong movement against it.

During my journey coding an actuator for a non-Spring Boot application, I came upon an interesting problem regarding where to actually put a snippet of common code. This post tries to list all available options, and their respective pros and cons in a specific context. As a concrete example, let’s use the REST endpoint returning the map of all JVM properties accessible through the /jvmprops sub-context. Furthermore, I wanted to offer the option to search not only for a single property e.

Working on a legacy project those last weeks gave me plenty of material to write about tests, Mockito and PowerMock. Last week, I wrote about abusing PowerMock. However, this doesn’t mean that you should never use PowerMock; only that if its usage is commonplace, it’s a code smell. In this article, I’d like to show an example how one can refactor legacy code to a more testable design with the temporary help of PowerMock.