Java

AWS Cost Optimization for Microservices: ECS vs EKS vs Lambda

The runtime question usually arrives disguised as a cost question: “our AWS bill is too high, should we move to serverless?” Almost always the honest answer is that the runtime is not the biggest line on the invoice — but the runtime decision does determine which levers you get to pull later, so it is worth making deliberately. This is the decision framework I use for Java services, and the levers that have moved real bills.

Monday, August 17, 2026 | 6 minutes Read

Kubernetes Deployments for Java Microservices: Rolling, Blue/Green, and Canary

Not every change carries the same risk. A copy fix and a rewrite of the pricing logic do not need the same rollout mechanics, and treating them the same means you either move too slowly or find out about a regression from your users. This is how I pick between rolling updates, blue/green and canary for Java services — and the JVM-specific details that make all three behave differently than the tutorials suggest.

Monday, August 17, 2026 | 6 minutes Read

Spring Boot Production-Ready Checklist (2026)

Shipping a Spring Boot service is easy. Keeping it fast, secure and operable at three in the morning is the hard part. This is the checklist I walk through before a rollout — condensed from services I have taken to production on Kubernetes over the last few years, currently on Spring Boot 4 and Java 25. It is deliberately not a list of everything you could do. It is the set of things whose absence has cost me, or a team I worked with, an incident.

Monday, August 17, 2026 | 7 minutes Read

Generating data with Mockneat

At some point every developer reaches the point where they need larger amounts of data. One open-source library I like to use is Mockneat. The Mockneat library offers an easy-to-read API to generate JSON, XML, CSV, SQL and whole POJOs. The nice thing about it is that you can generate valid data with little effort. Just a foretaste of what Mockneat can generate without much effort: If something is still missing, I can fall back on a regular expression:

Friday, January 3, 2020 | 1 minute Read

Spock Testing-Framework

First of all, Spock and JUnit are both great test frameworks, and JUnit is usually one of the standard tools I reach for in a project. In my last project a colleague suggested Spock, and we decided to try it out in one of our microservices and roll it out everywhere if we liked it — which we finally did. You can find all examples here on GitHub, of course.

Sunday, October 20, 2019 | 3 minutes Read