A Java geek

Maps without a tile server

If you have built an application with an interactive map, you know what you are in for. You pick a tile provider such as Google or Mapbox, or a self-hosted stack like GeoServer or Martin, and your frontend requests thousands of small image or vector tiles as the user interacts with the map. A server processes each request: it reads from a database, renders the tile, maybe caches it, and sends it back. That server is infrastructure: it needs to be deployed, monitored, and scaled.

Technical

Scraping websites and bot-protection

While searching for my ancestors, I had to access data from many different websites. I noticed there were different levels of protection against automated access depending on the site. In this post, I’ll list them and mention countermeasures you can take to bypass them anyway. Disclaimer As a private person using the data for my own personal use, I have no qualms about bypassing the protection. It can be considered fair use.

Technical

Security Baked Into the JVM: no single party controls the outcome

A URL is a name, and names get reused. Replace the bytes behind https://repo.example.org/order-processor.jar and every permission granted to that URL still applies, now to code nobody audited. So far in this series, Part 1 declared constraints on a remote call, Part 2 vetted code before a client loaded it, Part 3 established who is calling, and Part 4 carried that chain of identities across the wire.

Development

From documenting decisions to questioning them

I started with a simple task: I needed an AI agent to help me compile decision records, structured documents that capture why a team chose option A over B, using the open-source MADR format. Fill in the sections, organize the rationale, done. It worked. And it was useless.

Technical

AI-assisted genealogy, a follow-up

I got a lot of feedback on my post AI-assisted genealogy, some good, some not so good. In any case, I felt the subject was interesting to a lot of people. Meanwhile, I continue working on my tree, and I have deepened my understanding of the subject. In this post, I want to share again. Trust, but verify Let’s address the not-so-good feedback first. The gist of it was: AI can hallucinate. It’s true in theory: when you ask a question, it provides any answer.

Miscellaneous

World geography gotchas

Years ago, a colleague of mine told me about two pockets of foreign land surrounded by Switzerland: Campione d’Italia and Büsingen am Hochrhein, respectively Italy and Germany. Both are enclaves of their respective country in Swiss territory: An enclave is a part of the territory of a state that is enclosed within the territory of another state. To distinguish the parts of a state entirely enclosed in a single other state, they are called true enclaves.

Book

Build an AI Agent (From Scratch)

Facts 10 chapters$29.29 (at the time of this writing)315 pages Chapters Building your first LLM agentWhat is an AI agent?

Technical

AI-assisted genealogy

My son recently came to me to brag about using AI to find our ancestors. While the results were correct, I didn’t learn anything new, as it stopped at my grandparents. I was never very interested in my genealogy, but I decided to see if AI would be a good tool for this. TL;DR: Yes, it is, and even more than that. In a little less than one month, I managed to gather more than 600 individuals and get back 12 generations in some branches.

Technical

Security Baked Into the JVM: sixteen Subjects on the wire

Alice calls the order service. The order service calls the ledger on her behalf. At the second hop, the ledger has to decide whose authority the debit is being made under. Most stacks answer badly. Forward Alice’s bearer token verbatim, and the ledger cannot tell her from the service that relayed it. Drop the token and the ledger sees a machine, with no record that a human started the chain. Neither option lets the ledger authorize the combination.

A Java geek

Nicolas Fränkel's blog