First Real Vibe-Coding Experience

Yesterday evening we had some friends over. The guy is a very experienced Java dev (15+ YOE), and we talked about dev stuff and, of course, AI and coding assistants. His company (a fairly large enterprise in Germany) had banned all use of AI. They’ve now backtracked a bit, but are still “looking into it and evaluating.”

I told him about my experiments with Claude Code. He was skeptical, but acknowledged that for some use cases these tools are a big help. But I got him curious. We had about an hour before they had to leave, so we grabbed some beers, my MacBook, and a use case he had in mind.

In Germany, there’s this thing in schools called Elternvertreter — each class must elect a parent rep and a deputy. It’s part of school law. The election is usually the most annoying part of the first parent meeting — if nobody volunteers, the meeting drags on until someone gives in. Been there, done that. 11 pm on a Tuesday.

The election must be fair, voluntary, and anonymous. Most teachers hand out slips of paper, tally the votes, and that’s it. But in six years of having school-aged kids, I’ve never seen real “competition.” Everyone’s just glad when someone steps up.

So, my friend imagined a simple desktop app: runs locally, no auth, lets parents vote turn by turn, and spits out a nice PDF you can send around. Nothing fancy.

Long story short — I decided to vibe-code the app. I’ve got no real Java experience — my last touchpoint was 10+ years ago. No IDE set up, and we had just under an hour. I fired up Claude, wrote a quick CLAUDE.md (10 min), and off we went. Genie brainstormed JavaFX + SQLite — exactly what my friend had in mind.

10 minutes in, we had a version that compiled and started. Created a voting session, added parents, picked the “volunteers.” Kept adding functionality and testing. A few bugs and loose ends (buttons without function), but nothing serious. After 45 minutes, we had a working app — and I hadn’t even looked at the code. Just tossed in some refactoring rounds, auto-accepted all the Genie’s suggestions.

Pretty cool experiment, especially with a stack I don’t know and barely any time. Very different from my previous Genie experiments.

After our friends left, I kept playing around. Eventually looked into the code. I’m no Java expert, but structure, model, patterns — all looked “good enough” to me. I’ll drop a repo link in the comments — feel free to comment on it.

And yeah — my friend was seriously impressed!