Tag
How a duplicate-payouts report from finance taught me that idempotency is a system property, not a one-service bug fix — and the path from a tactical patch to a cross-cutting framework that took at-least-once seriously.
A "simple" lost-update bug took me through optimistic locking, pessimistic locking, and finally a two-stage Redis-locked aggregator — a tour of why the right concurrency primitive depends entirely on the shape of your contention.
A routine scale-up from one pod to three exposed an architectural assumption I'd been making for years — that Spring's in-memory STOMP broker could survive horizontal scaling. It can't. Here's the Redis Pub/Sub fan-out pattern that fixed it.
A UX complaint led me to one of the most underrated primitives in the Kafka client — consumer.pause(). Here's how a 2-second delay problem ruled out three reasonable approaches and ended up at a pause/resume pattern with a TaskScheduler.
How to actually build microservices on the JVM — the frameworks that matter, the patterns you'll reach for, and concrete code for a small order-processing system built with Spring Boot.
The parts of Spring Boot you'll use on every project, the parts you'll almost never touch, and the mental model that separates the two.