Every developer has a blog they keep meaning to start. This is mine.
I’ve been a backend engineer for a few years now, mostly working with Java and Spring Boot on large-scale systems. Along the way I’ve accumulated a lot of notes, debugging steps, architectural decisions, AWS gotchas, the occasional frontend struggle. Most of them live in handwritten notes, Notepad++, Obsidian, and the occasional PlantUML or Mermaid diagram. I’ve also shared some of these notes with colleagues on Teams, and sometimes on Slack.
This blog is where those notes graduate to.
Why “Errors”?#
Because errors are where the real learning happens. Not the clean tutorial code that compiles on the first try (but never works as expected), the NullPointerException at 2am, the CloudFormation stack that rolls back for reasons nobody understands, the Spring Boot config that works locally but not in production.
What You’ll Find Here#
- Java & Spring Boot — the stuff I work with every day. Patterns, pitfalls, performance tuning.
- AWS — Lambda, DynamoDB, Glue, EventBridge, CloudFormation just to name a few. Real-world usage, not just docs rewrites.
- Vaadin — currently learning this for full-stack Java web apps.
- Next.js & Frontend — not my strong suit, but I’m working on it.
- Architecture — DDD, event-driven systems, scaling things that need to handle millions of requests.
- Teaching & Learning — sometimes the best way to learn something is to explain it to someone else.
The Format#
Some posts will be proper tutorials. Some will be rough notes — the kind of thing I’d search for six months from now when I hit the same problem again. Some might be written by collaborators.
No bullsh*t. Just code, context, and the occasional opinion.
void main() {
IO.println("Let's get started.");
IO.println("// Danko.");
}If you want to know more about me, check the about page.