A software engineering journal
Notes on Java, architecture, and the tools we use to build better software. Written by Andrés Tascón.
01 / The journal
A step-by-step setup for sharing agent settings, instructions and skills between Windows, macOS and Linux machines with one private Git repo and an install script, including what to do when the second machine already has its own configuration.
A reproducible Jev effort recommendation, the commands to apply it in Codex and Claude Code, and the cache and cost tradeoffs I still need to measure.
A practical guide to testing strategy for Java backend systems — from unit tests with JUnit and Mockito, to integration tests with Testcontainers, contract tests with Pact, and concurrency tests that catch race conditions. Includes a complete fintech wallet example.
Scoped Values are production-ready, object headers just got smaller, and you can finally write code before super(). Here's why Java 25 is the LTS release you shouldn't skip.
A practical guide to building Model Context Protocol servers — covering tools, resources, and prompts, plus the rules that separate production servers from proof-of-concepts.
A practical guide to Atomicity, Consistency, Isolation, and Durability — with SQL examples and a bank transfer walkthrough showing all four properties in action.
02 / Put it into practice
70 questions to sharpen your understanding of the ideas behind the code.