JUGtoberfest 2025 - Threads, GitHub & Rock'n'roll

Join us for an evening that combines high-quality technical talks with the friendly, festive spirit of JUGtoberfest. Three talks, three experts, and plenty of time for networking — whether you’re into language design, large-scale engineering, or runtime internals, there’s something for you.

## Daniel Kec (Oracle, Helidon) — Brief history of Virtual Threads

Talk (short): Threading in Java has a long and exciting history. Daniel will take us from green threads through native threads, explain the limitations that motivated Project Loom, cover continuations and Loom’s design, and compare reactive approaches to modern Virtual Threads. He’ll also show how modern microservice runtimes support Virtual Threads — with examples from Helidon 4.
About Daniel: Daniel works at Oracle on the Helidon project, contributing to Reactive Operators, Reactive Messaging and Long-Running Actions. A long-time enthusiast of reactive architectures, Daniel’s recent work with Project Loom and Virtual Threads brings practical insights into how these features change real-world runtimes.

## Mateusz Kamiński (Sages) — [PL] Farewell Kotlin, welcome new Java

Talk (short): Java turns 30 this year — and it’s experiencing a renaissance. Mateusz will examine whether Java’s recent evolution (language features, SDK additions and JVM improvements) is closing the gap with languages like Kotlin, what the future might hold, and when it makes sense to prefer one over the other.
About Mateusz: Mateusz is a Technology Evangelist & Trainer at Sages and a graduate of Warsaw University of Technology. He has led Java teams for many years, focuses on software architecture and performant Java programming, and now spends much of his time mentoring and delivering training.

## Bartosz Gałek (Allegro) — How Allegro keeps 13K GitHub repositories in check?

Talk (short): Operating a GitHub organization with ~13,000 repositories raises unique scale problems: duplication, technical debt, and coordinated changes. Bartosz will share how Allegro automates maintenance, manages large-scale Gradle projects, performs mass migrations and breaking changes, and balances automation with developer experience using tools like Gradle init scripts, OpenRewrite and custom PR managers. Expect practical lessons and cautionary tales.
About Bartosz: Bartosz is a Principal Engineer at Allegro, an open-source contributor and DevOps advocate. Full of energy (no coffee required!), he loves hackathons and board games. He brings hands-on experience in large-scale Java engineering and pragmatic tooling.

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### After the talks

As always, after the technical sessions we’ll have time for networking, Q&A with the speakers and a relaxed Oktoberfest-style atmosphere — drinks, chats and community vibes. 🍻