Amsterdam JUG meetup with Victor Rentea

Join in with the latest Amsterdam JUG Meetup at Code Nomads and OpenValue office.

For more details and discussions on the below, go to bit.ly/join-foojay-slack to join the Friends of OpenJDK (Foojay.io) Slack and use the #jug-amsterdam channel for conversations related to the below.

Program:

• 17:00 - Doors Open (And Food!)
• 18:00 - 18:45 Talk 1: Artem Makarov—Hacked in Translation: Reverse Engineering an Abandoned IoT Device
• 19:00 - 19:45 Talk 2: Philipp Fehre and Mike Petruzelli—OpenFeature in Production: Introducing Feature Flags at Mollie
• 20:00 - 20:45 Talk 3: Victor Rentea—Event-Based Integration Pitfalls
• 20:45: Networking

Abstracts:

Hacked in translation: Reverse Engineering an Abandoned IoT Device (Artem Makarov)

As everybody knows, "L" in IoT stands for long-term support. I'll take you on a tour of my technical adventure where I revived an abandoned IoT "AI" translator and gave it a new life, 2025-style.

Through deciphering peculiar protocols and formats, reverse engineering firmware and software and doing the necessary research to implement a replacement, we'll see how curiosity and persistence can help you overcome the most obscure technical challenges.

OpenFeature in Production: Introducing Feature Flags at Mollie (Philipp Fehre and Mike Petruzelli)

Founded in 2004, in 2023 Mollie made its journey into GCP, and deeper into the Java world. While Mollie has been a user of feature flagging for customers for a long time, with an implementation tied to the monolith, the journey into a multiservice Cloud world was not obvious. Born out of a focus on reliability, feature flags for all services were first introduced mid 2023, with one clear decision early on: to bet on OpenFeature to avoid vendor lock-in. Since then, the infrastructure has evolved and is now fully embracing open source, by self-hosting a flagd based backend.

This is also a story about taking an iterative approach to core infrastructure components, based on lasting decisions: betting on OpenFeature, embracing open source with flagd. Flagd and other backend components have been running in production now for some time, serving as the backend for feature flags for some of Mollie's most critical components in the payment infrastructure.

Event-Based Integration Pitfalls (Victor Rentea)

You publish Events instead of performing REST calls. What can go wrong? Join this tour of the top pitfalls and core patterns of Event-Driven Architectures:

• duplicated messages
• out-of-order
• race bugs
• request-reply
• error handling
• observability
• security
• privacy issues

Collected with love from 150 companies!

Bios:

About Artem. Artem Makarov is a Principal Engineer at Code Nomads. He's been working on Java projects in various industries for the past 14 years. Having Masters in Electronics Engineering he is passionate for applying engineering practices in his projects, contributing to better software design and reliability. In his free time he enjoys traveling, road cycling and learning to play music instruments.

About Philipp. Backend engineer for the almost two decades, normally found in JVM land exploring reliability and infrastructure.

About Mike. A seasoned Site Reliability Engineer with a background in building and scaling resilient systems across fintech, SaaS, and government sectors. Focusing on reliability strategy, incident response, and observability. Devoting attention to driving adoption of SLO-based practices, and building a culture of learning through chaos engineering, post-incident reviews, and automation at scale.

About Victor. With two decades of experience, Victor is a Java Champion and Software Architect who has dedicated his career to inspiring thousands of engineers through intense and entertaining workshops. The lessons he learned from a decade of training at 150+ companies, Victor turned into countless talks at top-rated conferences, where he became known as “the guy with the soundboard”. In his (very little) spare time, he does coaching and consultancy, and organizes online meetups for European Software Crafters, the world’s largest developer community about improving code quality. Discover his training topics at https://victorrentea.ro