Amsterdam Java User Group

From Elliptic Curves to Deploying on Friday Afternoons

Thu, Mar 19 · 5:30 PM CET

Danzigerkade 15B, 15B Danzigerkade, Amsterdam, NL

This meetup will be hosted by IKEA, in their office, Ingka Group Digital Hub (Amshult) Danzigerkade 15B, 1013 AP Amsterdam.

Note: After 18:30, IKEA's doors will close (this is from the building, we cannot change it unfortunately) so make sure to arrive before then.

Agenda

17:30 Doors open, drinks, and welcome to IKEA!

18:30 Erwin Manders (Rabobank) presenting “Elliptic Curve Cryptography Unleashed: Faster, Smaller, Stronger”

19:00 Break

19:15 Bas Stoker (independent contractor) presenting “Deploying On Friday Afternoons Without Stress”

19:45 Break

20:00 Surprise speaker, to be announced.

20:45 End

Information about the talks:

Title: "Elliptic Curve Cryptography Unleashed: Faster, Smaller, Stronger"

In a digital world overflowing with AI‑generated voices, deepfakes, and synthetic identities, one question rises above the noise: how can we still trust anything we read or receive? When every message could be fabricated and every sender could be an illusion, authenticity becomes a battlefield?

This talk dives into the cryptographic machinery that keeps that battlefield from collapsing. You’ll discover how asymmetric key cryptography lets us verify a sender’s identity without ever touching their secrets, and how a simple pair of cryptographic keys can anchor trust in a chaotic information landscape.

We’ll explore the elegance of elliptic‑curve cryptography, the hidden dangers of weak randomness, and the looming challenge of post‑quantum algorithms that threaten to upend everything we rely on today.

If you want to understand how digital trust survives in an era of manufactured reality, this is where the story begins.

About Erwin Manders. Erwin is a Solution Architect in the Online Access Management area of Tribe Digital Platform at Rabobank. He has been an architect for several years with hands-on experience as a Java developer and is certified as an architect in the ArchiMate framework. Erwin works primarily on Identity Management, Access Control, Data Integrity & Cryptography.

Title: “Deploying On Friday Afternoons Without Stress”

Keep deploying to production, and without stress? But in an environment where high availability is key, that's not as easy as it sounds… Because is monitoring alone really enough to head into the weekend with peace of mind? How do you safeguard quality while wanting to automatically deploy every PR to production? Also a bit tired of the simple tutorials explaining how to test, where the examples look nothing like your own project?

Then this session is really for you! In this case study of a real and non-trivial project at NS (Dutch Railways), I want to show you how we managed to pull that off, and how we leveraged modern tools like Testcontainers and Microsoft Playwright.

About Bas Stoker. Bas is a Senior Full Stack developer with a focus on Java and React. Main interests that unite both worlds are creating nice customer experiences and QA-topics and associated tooling and best practices, e.g. Testcontainers and Docker-based deployments like Kubernetes.

Amsterdam JUG Meetup at Picnic

Tue, Mar 24 · 5:00 PM CET

Picnic, Van Marwijk Kooystraat 15, Amsterdam, al, NL

Join in with the latest Amsterdam JUG Meetup at Picnic HQ, Van Marwijk Kooystraat 15, 1114 AG Amsterdam.

Agenda

17:00 - Doors Open (And Food!)
17:30 - 18:00 Talk 1: "Raising Young Coders" by Cassandra Chin from CNCF
18:00 - 18:30 Talk 2: "Java 25 in Production: Memory Dieting to Tame Latency and Garbage Collection" by Manish Askani from Picnic
18:30 Short Break
18:45 - 19:15 Talk 3: "MCP in Practice with Kafka" by Jeroen van Disseldorp from Axual
19:15 - 19:45 Talk 4: "Connecting the Dots with Context Graphs" by Stephen Chin from Neo4J
19:45 - 20:15 Talk 5: "Scripting on the JVM with Java, Scala, and Kotlin" by Li Haoyi
20:15 - Networking drinks
21:00 - End

Talk 1: Raising Young Coders

Teaching kids programming at a young age is really important to improve diversity in the field of computer science. Studies show that after middle school most students have already made up their mind about a career in computers, so having a positive introduction to computers at a young age is really important.

I wrote a book on Raising Young Coders published with Apress to teach tech and non-tech parents how they can inspire their kids to love technology. I also teach workshops for underprivileged kids around the world at events like CNCF Kids Day and want programming to be fun and engaging just like how I learned to program.

I will share some of the techniques I use to get kids excited about technology, which you can use to teach your own kids or others.

Talk 2: Java 25 in Production: Memory Dieting to Tame Latency and Garbage Collection

Upgrading to a new Java version is often driven by the desire for new language features, or the need to stay current with security updates. In this talk, we show how moving to Java 25 became a turning point for fixing severe tail-latency and GC instability in a high-throughput production system at Picnic.

This talk presents a real-world case where upgrading to Java 25 resolved severe tail-latency and GC issues in a high-throughput system. It covers JVM memory tuning, leveraging Compact Object Headers, and counterintuitive strategies—like shrinking the heap—for improved latency and GC stability, offering practical advice for backend and platform engineers.

Talk 3: MCP in Practice with Kafka

This talk explores MCP through a practical, Kafka-centered case study. It demonstrates how high-level intent expressed in natural language can be translated into controlled Kafka operations such as topic provisioning, access management, and application deployment. The session also illustrates how MCP can be combined with declarative approaches like a YAML-based DSL for stream processing to generate and deploy streaming applications without requiring direct Java development.

Over the past year, the Model Context Protocol (MCP) has generated significant attention as organizations explore more reliable ways for AI systems to interact with real infrastructure. As AI assistants move beyond conversational use cases and begin executing operational tasks, a key challenge is ensuring those interactions are secure, predictable, and governed by clearly defined constraints. MCP addresses this by providing a structured framework that enables AI systems to discover capabilities, interpret context, and invoke external tools through explicit, well-defined contracts.

Talk 4: Connecting the Dots with Context Graphs

AI systems need more than intelligence; they need context that persists. Without it, even strong models can misinterpret information, lose decision rationale, or repeat the same mistakes. Context Graphs have emerged as a practical pattern for agentic AI: a living graph that captures not only what was retrieved or known, but how context led to actions through tool calls, constraints, policies, and outcomes, stitched across entities and time so precedent becomes searchable.

This talk explores context engineering as the discipline of designing that context layer, and shows how context graphs complement retrieval by enabling multi-hop, structured context assembly (building on GraphRAG-style hierarchical summaries) while improving explainability and evaluation. Attendees will leave with a practical understanding of how to build context pipelines that combine contextual retrieval with persistent memory and provenance, and why context graphs are becoming central to trustworthy, enterprise-ready AI systems.

Talk 5: Scripting on the JVM with Java, Scala, and Kotlin

This talk will explore the usage of JVM languages as scripting languages, replacing the Bash and Python scripts common throughout the industry. We will walk through live-coded demonstrations of how the JVM's benefits of performance, compile-time safety, and vast library ecosystem are advantages over traditional script platforms, but also how language verbosity, build tool overhead, and lack of convenient libraries hampers the efforts.

Lastly, we will demonstrate how script-focused tooling is able to smooth over some of those issues, simplifying build configuration and providing suitable libraries to make the JVM truly a world-class scripting environment as robust as any scripting language out there.

Bios:

Cassandra Chin has given keynotes at Devnexus, JFokus, Devoxx Belgium, and Devoxx Morocco. Her latest book, Raising Young Coders, is published by Apress and helps parents to inspire their kids to love technology. She has been teaching technology kids workshops at international conferences since she was 13 years old and is passionate about helping allow women, minorities, and underprivileged students to learn about technology. Her books have been featured at international events like Kubecon + CloudNativeCon and in popular technology shows like theCUBE and Techstrong TV. More here...

Manish Askani is a Staff Engineer at Picnic Technologies, where he focuses on Operational Excellence in the Consumer domain. His work centers on improving production reliability, latency, and performance of high-throughput Java systems used by millions of users. Manish spends most of his time deep in JVM behavior, garbage collection and memory performance, translating low-level runtime mechanics into practical improvements for real production workloads. He has led multiple initiatives around incident reduction, performance stability, and deployment resilience and regularly works at the intersection of platform engineering and application architecture. More on LinkedIn here.

Jeroen van Disseldorp is a technology entrepreneur, CTO, and founder of Axual ("Kafka done right: European. Governed. Future-proof.") with a passion for real-time data and event-driven architectures. With years of experience designing scalable distributed systems, he focuses on making complex streaming technologies practical and accessible for teams. Jeroen is enthusiastic about energy and sustainability and is particularly interested in how innovation and data can contribute to a more sustainable future. More on LinkedIn here.

Stephen Chin is VP of Developer Relations at Neo4j, program chair of the LF AI & Data Foundation, and author of numerous titles including the upcoming GraphRAG: The Definitive Guide for O'Reilly. He has given keynotes and main stage talks at numerous conferences around the world including AI Engineer Summit, AI DevSummit, Devoxx, DevNexus, JNation, JavaOne, Shift, Joker, swampUP, and GIDS. Stephen is an avid motorcyclist who has done evangelism tours in Europe, Japan, and Brazil, interviewing developers in their natural habitat. When he is not traveling, he enjoys teaching kids how to do AI, embedded, and robot programming together with his daughters. More here...

Li Haoyi graduated from MIT, has built infrastructure for high-growth companies like Dropbox and Databricks, and has been a major contributor to the open source community with over 10,000 stars on Github. Haoyi has deep experience in the JVM and has used it professionally to build cloud infrastructure, distributed backend systems, programming languages, high-performance web applications, and much more. More here....