I started as a Java developer, but for some time now, I have broadened my horizons. Recently, I thought about how early languages were dedicated to a single target and platform, and now they are broadening their focus. In this post, I want to write down my thoughts in the hope that it may be useful to others, probably to my future self. Definitions You may have been wondering about the title…

There is an evergreen debate in the Java world: should you always use BigDecimal for money? The short answer is no. The real answer is: it depends on your computational context: the precision you need, the rounding rules you must follow, and the performance budget you have. The problem is that this conversation is often driven by dogma rather than engineering.

In the first post of this series, I focused on the project foundations: what should I do to create a video from photos taken from the same position year after year? I dedicated the second part to aligning images. It wasn’t as easy as I expected. I stumbled upon new concepts, such as ORB and RANSAC. In this third and final post, I want to tackle the video creation itself, explain some 'artistic'…

Before working for 2 years on the Apache APISIX API gateway, I was mainly oblivious to API gateways. It’s only by working with them that I understood their value. Decoupling the client and the server unlocks a lot of options: moving authentication to the API Gateway, securing APIs, deduplicating API requests, etc. In this post, I want to describe how the same pattern applies to AI. AI gateways AI…

In the previous post, I described the Seasons project: a time-lapse of hundreds of pictures taken from nearly the same viewpoint over the years. The hardest challenge wasn’t taking the pictures or assembling them, but aligning them. You might have noticed the nearly part about viewpoint in the above paragraph. Indeed, it’s an approximation. I’m a human being, not a tripod. The position changes…

I live close to nature. I regularly go for a run in the countryside. Over several years, during my runs, I’ve taken pictures from the same position, always roughly the same angle. I had a vague idea in the back of my mind, as an 'artistic' project. One day, I’d turn those photos into a time-lapse video, one that would show the passage of seasons across a single place. Spoiler, here’s the work in…

Good engineers make decisions based on data. Most businesses assumed that the more data, the better the decision. Then, several factors put a halt to the hoarding of ever more data. GDPR and its localized counterparts, and the cost of storage. However, before the GDPR came into effect, the Datensparsamkeit approach already existed. Datensparsamkeit is a German word that’s difficult to translate…

I don’t think it’s necessary to introduce Gregor Hohpe. I’m a big fan, having read Enterprise Integration Patterns, and I’ve recommended the book ever since. When I spoke at the Software Architecture Gathering in 2024, I was fortunate enough to meet him and purchase this book. I’m the happy owner of a signed copy. Modern architects don’t try to be the smartest people in the room–they make…

I like to analyze codebases I start working on, or that I left for months. I ask my coding assistant, case in point, Copilot CLI: 'analyze the following codebase and report to me improvements and possible bugs.' It’s vague enough to leave room for crappy feedback, but also for some interesting insights. I did it last week on a code base. Copilot returned a list of a dozen items. I asked it to…

As I age, I become increasingly cautious about my privacy. The slope the world is sliding on is also a big, unfortunate incentive. I have been eying Pi-hole for some time: in this post, I want to explain what it does, how to install it on a Raspberry Pi, and how to integrate it with Tailscale. My take on privacy Privacy, or more specifically digital privacy, is the ability to protect oneself…

vCluster is a solution for creating virtual clusters within a host Kubernetes cluster. Virtual clusters are a Kubernetes concept that enables isolated clusters to be run within a single physical Kubernetes cluster. Each cluster has its own API server, which makes them better isolated than namespaces and more affordable than separate Kubernetes clusters. — What are virtual clusters?

Most developers now use coding assistants. I do too—Copilot at work, Claude Code at home. As a developer, I prefer not to repeat myself. This post explains why and how to avoid repetition as a skill. Don’t Repeat Yourself The DRY principle has been present in the software development field for ages. The idea is that if you copy and paste code in multiple places and a bug appears, you’ll need to…

Leading your organization to use OpenTelemetry is a challenge. In addition to all the usual project hurdles, you’ll face one of these two situations: convince your teams to use OpenTelemetry, or convince them to move from the telemetry tool they are already using to OpenTelemetry. Most people don’t want to change. You’ll need lots of effort and baby steps. My tip is the following: the fewer the…

For as long as I have been coding in Java, we have had requirements to measure the execution time of blocks of code. While the current good practice is to use OpenTelemetry’s traces, not every company has reached this stage yet. Plus, some of the alternatives are OpenTelemetry-compatible. Let’s see them in order. The basic option The basic option is what we have been doing for ages, and what the…

Last month, I became aware of GitHub agentic workflows. I read the site carefully, but the use cases weren’t very exciting to me. I tried the continuous documentation It didn’t work out initially, and because of my lack of involvement, I left it as it was. However, I succeeded in another one that I want to describe in this post. With lessons learned here, I managed to make the documentation…

A couple of years ago, I wrote that The Builder pattern is a finite state machine!. A state machine consists of states and transitions between them. As a developer, I want to make illegal states unrepresentable, i.e., users of my API can’t create non-existent transitions. My hypothesis is that only a static typing system allows this at compile-time. Dynamic typing systems rely on runtime…

When you think of Java modularity, chances are your first thoughts land on JPMS, or perhaps on Spring’s flexible configuration model. For those who 'experienced' like me, thought can reach OSGI specification or other stacks like Vert-X. Yet long before either, Java offered a minimal yet powerful mechanism for loose coupling: ServiceLoader. In this article, we’ll explore what ServiceLoader is,…

I noticed some time ago that three Mastodon features had stopped working on my blog. Each of them seemed like a separate problem, but they had the same root cause. In this blog post, I aim to describe these issues and propose a simple solution. Domain verification Mastodon allows you to prove that you own a domain.

Most of my blog posts are lessons learned. I’m trying to achieve something, and I document the process I used to do it. This one is one of the few where, in the end, I didn’t achieve what I wanted. In this post, I aim to explain what I learned from trying to migrate from Jekyll to Hugo, and why, in the end, I didn’t take the final step. Context I started this blog on WordPress. After several…

I continue to experiment with AI in the context of software engineering. I’m fortunate that my team supports me in exploring different ways to improve our daily work. This week, I designed a team of autonomous agents to implement features, from design to implementation. Why autonomous agents? A long time ago, we were delighted when the IDE offered auto-completion. In the previous two years,…