Java Concurrency

Spots are limited: [https://tickets.voxxeddays.com/event/workshop-victor-rentea](https://tickets.voxxeddays.com/event/workshop-victor-rentea) **Build faster, smarter software with AI.** Join an exclusive, fully catered workshop with Victor Rentea on Agentic Engineering in a small, focused group of engineers. **Upgrade your development workflow to 2026.** A hands-on day on AI Coding Agents: prompt & context engineering, multi-agent orchestration, spec-driven development, and self-improving skills. Learn how engineers reach 2x–10x productivity and what it takes to get there. **For:** all engineers (backend, frontend, QA, data, ops) **Bring:** laptop with Claude Code + subscription (Pro is enough) **The agenda of the day** **Introduction** * LLM Fundamentals: Predictions, Tokens, Context Window, Compaction, System Prompt, Model vs Agent Harness * AI Pitfalls: Sycophancy, Hallucinations, Attention Dilution, Knowledge Cutoff, Premature Fixation * MCP Tools – best-of **Context Engineering** * Evolving a Token-Efficient Project Memory * AI Context Sharing across repos, teams, and company * Skills and Custom Agents that self-improve * Token-Efficiency Tricks: context hygiene, DRY, grep-logs antipattern **Prompt Engineering & Orchestration** * Prompt Engineering – does and dont’s * Brainstorm, plan & generate a non-trivial change with AI * Multi-Agent Orchestration Patterns: handover, reviewer, orchestrator, advisor,… **AI Guardrails & Security** * Functional Guardrails with State-of-the-art Acceptance Tests * ⁠Code Quality Guardrails AI cannot circumvent * ⁠Architecture Guardrails & Exact Summarisation * APIs, C4 Model, sequence diagrams * AI Supply-Chain Attacks Attacks and Agent Isolation Techniques **Date:** Wednesday, July 1st (09:00 - 17:00) **Location**: Utrecht (venue TBA) **Price**: € 395,- (incl. lunch & drinks) Spots are limited: [https://tickets.voxxeddays.com/event/workshop-victor-rentea](https://tickets.voxxeddays.com/event/workshop-victor-rentea)

**[Simon Brown](https://www.linkedin.com/in/simonbrownjersey/) is the creator of the [C4 model for visualising software architecture](https://c4model.com/) and [Structurizr](https://docs.structurizr.com/) \- the original developer\-friendly "models as code" tooling for creating version\-controlled documentation\. He is the author of [The C4 Model](https://www.oreilly.com/library/view/the-c4-model/9798341660113/) (O'Reilly) and [Software Architecture for Developers](https://leanpub.com/software-architecture-for-developers) (Leanpub). Over the past 15+ years, Simon has worked with hundreds of organisations across \~40 countries, from startups to global household names in almost every industry sector, helping teams adopt the C4 model and communicate their software architecture more effectively.** Join in with an evening with Simon Brown at the latest Amsterdam JUG Meetup at [Miro, Fred. Roeskestraat 100, 1076 ED Amsterdam](https://maps.app.goo.gl/C4DMUkUEsCQ3pAUk9). In this meetup, in addition to food, drinks, and networking, you will experience two sessions with and by Simon Brown. Whether you are new to C4 or very experienced with it, you will find something for you during this event. **Agenda** **18:00 -** Doors Open (And Food!) **19:00 - 19:45** Talk 1: **"First Steps with C4"** **20:00** **\- 20:45** Talk 2: **"Ask Me Anything About C4"** **21:00 -** The End *Note that by submitting the registration form for this meetup and by signing up to this event, you acknowledge that you have read and agree to [Miro's Conduct and Content Standards](https://help.miro.com/hc/en-us/articles/17048504794002-Conduct-and-Content-Standards), [Miro Meetups Terms](https://assets.ctfassets.net/udc161ufuk3a/4IM3zndnoYgSRv2IMBKADA/2b6098ff298eb8a2e3b86ebbb481d08f/Miro_Meetup_Terms_and_Conditions__1_.pdf), and [Miro's Privacy Policy](https://miro.com/legal/privacy-policy/) and agree for Miro to use personal data it collects of yours for the purpose of sending communications, including marketing emails, to you.*

\# This meetup is around a third\-party organizer\, Focus Filmtheater\. You can either purchase your ticket online or right before the session\. **Seats are numbered**. # **Title**: Mama’ku **Language**: Dutch **Subtitles**: English **Length**: 75 min **Director**: Sven Peetoom, Aldo Agaatsz **More info**: https://www.focusarnhem.nl/agenda/english-subs-mamaku/ **Ticket link**: https://www.focusarnhem.nl/tickets/146153/ **Synopsis:** The new documentary by Sven Peetoom (*Tussen Wal en Schip – Geruisloos Indisch)*. An intimate film about choreographer and dancer Cheroney Pelupessy, who makes the journey to Indonesia for the first time together with her mother in search of a hidden family history. **How it works**: I will be at Focus around 18:30, where we can meet before the movie starts. You can message me to find us. Screening starts at 19:00. After the movie, we can have a drink together. Hope to see you soon!

Hi all! 🙂 On Wednesdays we welcome you to practice languages! If you want to practice a specific (uncommon) language, please send us a message so we can find some conversation partners for you on our mailing list! We hope to see you in Café Marktzicht! In the last year we had tables for the following languages: * Dutch * English * French * Italian * Spanish * Turkish\* * German\* * Portuguese\* * Danish\* * Norwegian\* * Russian\* * Arabic\* * Chinese\*\* * Japanese\*\* * Indonesian\*\* * * Most likely, but not every week present. \*\* - Rather rare ;-) If your language is not in this list, please let us know! We have a large database of Language Cafe visitors speaking 56 different languages! We might be able to connect you with a person that does speak the language you want to practice. In case you are not in our database yet, please use this form: http://goo.gl/forms/oSCn9Dn8m8

**When:** Wednesday\, July 1st \| 🕒 Doors open at 19:00\, battle starts at 20:00 **Where:** De Ping Pong Club, Utrecht **Damage:** €4,07 (Buy your tickets in advance as spaces are limited! Secure your spot directly with the venue [here](https://shop.weeztix.com/37dc63d6-519c-11f0-a9cb-7e126431635e/events?shop_code=5rn36dck)!) **The Vibe:** I checked out De Ping Pong Club last week—it is an awesome location! They even have board games if you need a break from the action. I played there recently outside of a tournament, and let me tell you about the "athletic" standard: if you can hold two beers at the same time, you are officially qualified. This is not the Olympics, this is [around the table](https://depingpongclub.nl/agenda/). Leave your sports watch at home; this is a purely social event where your actual speaking time will easily outlast your playtime. **Pro Tip:** There are bonus points for costumes and alternative, non-paddle equipment. Fry-pans, textbooks, or flip-flops? Bring it. **Essential Training Routine:** If you actually want to take this seriously and lift the trophy, you *must* complete this strict two-step preparation: 1. Watch the [Balls of Fury Trailer](https://www.youtube.com/watch?v=HXR_NLDMUk8&t) to master the illegal underground table tennis mindset. 2. Blast [Armin van Buuren's Ping Pong](https://www.youtube.com/watch?v=Z8V5GfFeUDs) on repeat to get your hand-eye coordination synced to 138 BPM. **P.S.** Who is willing to play in my team **"ExBats"**? (Yes, a terrible pun merging "Expats" with *bat*, the Dutch word for racket). Drop a comment below if you're in!

Welcome to our Volleyball community !! 🏐🎉 We are a community of volleyball enthusiasts who want to enjoy the game, improve their skills, and meet new friends. Our open play sessions offer a friendly, social environment where everyone can get some practice and have fun. Our sessions consist of mixed level play, however intermediate volleyball knowledge is mandatory. We try to have a balanced levels per team to ensure smooth play. If you aren’t familiar with basic volleyball rules and have no experience, sorry to say, but it's not your group. ❗❗ Meetup recently pops up their subscription option after you click on RSVP— you can dismiss it by clicking the "X" in the top left corner. ✅ RSVP & Attendance Attendance is limited to 14 people. If the RSVP list is full, join the waiting list—cancellations happen frequently. If the event appears full on the Meetup app, try using a web browser instead. ❌Cancellations & Refunds cancellation prior to 24h before the event, can be refunded. Can’t make it? Update your RSVP to "Not Going" ASAP so someone else can take your spot. 👟 What to Bring For your own safety and comfort, wear sport shoes and clothing (no street shoes—must change into sport shoes) and bring deodorant for ours. 💸 Payment & Contribution (€6.00 per person) Payment must be made in advance via Tikkie. Please only pay once you are added to the going list. In case you do not meet the payment deadline, you may be moved to the not going list. Looking forward to seeing you on the court! 🏐🔥 Let’s play, have fun, and make new friends!

Welcome to our Volleyball community !! 🏐🎉 We are a community of volleyball enthusiasts who want to enjoy the game, improve their skills, and meet new friends. Our open play sessions offer a friendly, social environment where everyone can get some practice and have fun. Our sessions consist of mixed level play, however intermediate volleyball knowledge is mandatory. We try to have a balanced levels per team to ensure smooth play. If you aren’t familiar with basic volleyball rules and have no experience, sorry to say, but it's not your group. ❗❗ Meetup recently pops up their subscription option after you click on RSVP— you can dismiss it by clicking the "X" in the top left corner. ✅ RSVP & Attendance Attendance is limited to 14 people. If the RSVP list is full, join the waiting list—cancellations happen frequently. If the event appears full on the Meetup app, try using a web browser instead. ❌Cancellations & Refunds cancellation prior to 24h before the event, can be refunded. Can’t make it? Update your RSVP to "Not Going" ASAP so someone else can take your spot. 👟 What to Bring For your own safety and comfort, wear sport shoes and clothing (no street shoes—must change into sport shoes) and bring deodorant for ours. 💸 Payment & Contribution (€6.00 per person) Payment must be made in advance via Tikkie (payment link will be send to you). Looking forward to seeing you on the court! 🏐🔥 Let’s play, have fun, and make new friends!

Codelab and the [Rabobank Tech Community](https://www.meetup.com/rabobank-tech-community/) are organising a Java meetup with Victor Rentea about: Agentic Engineering - Patterns and Anti-Patterns If you would like to join, subscribe quickly here (seats are limited): https://www.meetup.com/rabobank-tech-community/events/315294956 === **Agenda** 17:00 Walk in + Dinner 18:15 Talk 20:00 Drinks 21:00 Ending **Talk description** A compilation of emerging patterns and common pitfalls observed in over 50 companies. From unhealthy context management, naive prompting, unvetted AI slop, and careless supply-chain to self-learning skills, sub-agent orchestration, AI guardrails, and backpressure. Join this talk to cut through the hype, learn from the early adopters of agentic engineering – see what works, what ships better code 3x faster in production, and what fails **Speaker** Victor Rentea is a Java Champion and an Independent Trainer delivering intense webinars for dozens of companies worldwide since 2014. His passion is Simple Design, Refactoring, and Unit Testing, about which he regularly talks at top conferences, but also to the European Software Crafters Community that he founded. On victorrentea.ro you can find his blog, best talks, training curriculum, live masterclasses, and social channels.

The Rabobank Tech Community together with [CodeLab](https://www.meetup.com/codelabjug/) is organizing a Java meetup for our community. Victor Rentea will speak at Rabobank in the evening of July 2nd. Because of the limited number of seats, please keep your RSVP up-to-date, so we can welcome someone else if you can't make it. **IMPORTANT:** Due to Rabobank security measures, we need to present in advance an attendee list with everyone’s full names. This is partly because Rabobank is, well, a bank, but also related to safety measures in case of an emergency. That is why we need to ask you the following: If you do not use your real full name as profile name at Meetup.com, could you send us your full name in a private message? The attendee list presented to Rabobank will only be used for visitor's registration at the reception and will not be published anywhere, we only do this to comply with said safety measures. The meet-up will be held in a non-public area of the building. This means that without proper registration the security team will not be able to let you in. Hoping for your understanding. === **Agenda** 17:00 Walk in + Dinner 18:15 Talk 20:00 Drinks 21:00 Ending **Talk** **Agentic Engineering - Patterns and Anti-Patterns** A compilation of emerging patterns and common pitfalls observed in over 50 companies. From unhealthy context management, naive prompting, unvetted AI slop, and careless supply-chain to self-learning skills, sub-agent orchestration, AI guardrails, and backpressure. Join this talk to cut through the hype, learn from the early adopters of agentic engineering – see what works, what ships better code 3x faster in production, and what fails **Speaker** Victor Rentea is a Java Champion and an Independent Trainer delivering intense webinars for dozens of companies worldwide since 2014. His passion is Simple Design, Refactoring, and Unit Testing, about which he regularly talks at top conferences, but also to the European Software Crafters Community that he founded. On [victorrentea.ro](http://victorrentea.ro/) you can find his blog, best talks, training curriculum, live masterclasses, and social channels.

'THE SYMPATHIZER' by Viet Thanh Nguyen 'The winner of the 2016 Pulitzer Prize for Fiction, as well as seven other awards, The Sympathizer is the breakthrough novel of the year. With the pace and suspense of a thriller and prose that has been compared to Graham Greene and Saul Bellow, The Sympathizer is a sweeping epic of love and betrayal. The narrator, a communist double agent, is a man of two minds, a half-French, half-Vietnamese army captain who arranges to come to America after the Fall of Saigon, and while building a new life with other Vietnamese refugees in Los Angeles is secretly reporting back to his communist superiors in Vietnam. The Sympathizer is a blistering exploration of identity and America, a gripping espionage novel, and a powerful story of love and friendship.' ***Please read the book and join us for a lively discussion (in English) about the contents during our afternoon book club meeting.*** \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\- **PLEASE NOTE:** This is an IN-PERSON event in Amersfoort, The Netherlands. Please cancel your attendance in advance if you are unable to join, so that those on the waitlist can participate. Looking forward to seeing you all IN REAL LIFE then! Best regards, Sandra

**SUSE X I-share:** **Sprekers:** * [Hugo de Vries](https://www.linkedin.com/in/hugo-de-vries/) (Solution Architect) * [Bert Boerland](https://www.linkedin.com/in/bertboerland/) (Account Executive) * [Keown de Koning](https://www.linkedin.com/in/keowndekoning/) (Head of Channel) **Beschrijving** ''Tijdens deze sessie nemen we je mee door het brede SUSE-portfolio. Van de betrouwbare basis van SUSE Linux Enterprise Server (SLES) tot multicluster Kubernetes-beheer met Rancher en zero-trust containerbeveiliging met SUSE Security: SUSE biedt een compleet, onafhankelijk open-source ecosysteem van besturingssysteem tot cloudtechnologieën. We starten met de basis van SUSE en kijken terug naar de ontwikkeling van een Duitse open-source pionier in 1992 tot een wereldwijde enterprise speler van vandaag. Daarbij prikken we door de marketingverhalen heen en delen we praktijkvoorbeelden van organisaties die het volledige SUSE-portfolio inzetten om complexe infrastructuuruitdagingen op te lossen. Ook laten we zien hoe klanten de overstap maken van een Amerikaans georiënteerde infrastructuur naar een Europees alternatief. Tot slot geven we een live Rancher-demo, waarin je ziet hoe alle componenten naadloos samenwerken om moderne IT-landschappen te beveiligen, beheren en schaalbaar te maken. Wat kun je verwachten: * **Het volledige SUSE-verhaal** Hoe een Europese open-source pionier een complete technologiestack heeft opgebouwd – van operating system tot Kubernetes. * **Meer dan alleen containers** Inzicht in het bredere portfolio (Linux & Cloud Native) en waarom dit aansluit bij de behoeften van moderne enterprises. Inclusief mogelijkheden om jezelf hierin te laten opleiden tot specialist. * **Praktijkvoorbeelden uit de markt** Hoe organisaties het volledige ecosysteem gebruiken voor stabiliteit, compliance en schaalbaarheid en waarom SUSE steeds vaker de nieuwe standaard wordt. * **Live demo** Zie het portfolio in actie en ontdek hoe SUSE de volledige keten verbindt: van infrastructuur tot en met de applicatielaag. Of je nu infrastructure architect, platform engineer of security specialist bent: sluit aan en ontdek waarom het SUSE-portfolio perfect aansluit op jouw moderne infrastructuurstack!'' *Het programma zal deze avond als volgt zijn:* * Vanaf 17.15 u: inloop * Rond 17.30/18.00 u: eten * 18.30 u: start sessie * 20.00 u: afsluiting We zien jullie graag dan!

The Dutch Heuvelrug is a hilly and sandy ridge, running from Hilversum in the north to Rhenen in the south. This National Park is covered in forest, heather and stretches of sand and dunes. On this hike, we will explore the Heuvelrug from Den Dolder. This area is mostly forested, perfect for a (hot) summer’s day! **Where to meet**: we will meet at **10 am** at train station Den Dolder. We will return to the same train station around 3pm. **This hike is fully booked.** [You may register on my website for a place on the waitlist.](https://rewildyourself.nu/dutch-nature-hikes/)

grassroots meet up for women / mothers / in Amsterdam who want to bring their children into their fun, spiritual and festival-going lives! this looks like a very family friendly festival, 30 minutes drive from Amsterdam and I do believe it is accessible by public transport. please note: I am not affiliated with this event, just a new mom / family who are finding our way back to events and spaces we loved pre-baby, now ready to enjoy them with our toddler and connecting with like-minded people along the way :) https://wonderfeel.nl

I'm excited to host the 25st edition of *Strangers to Friends*! Every event so far has been warm, fun and full of great connections. So we’re doing it again! Curious about our previous events? Check out our photo albums (only visible on the laptop version of Meetup). **What to expect** * A safe, relaxed environment to meet both locals and expats, whether you want to meet new people, experience an international atmosphere or talk about business, it’s all possible. * Start the evening with a few rounds of conversation cards: pair up with someone you don’t know, answer meaningful questions and rotate every 10 minutes. Within just one hour, you’ll get to know several people really well and enjoy meaningful conversations. * Everyone comes on their own, so it’s easy to connect. **Practical details** * Doors open at 20:00, after 30 minutes we start with conversation cards * Venue: Boekencafé Libertas, Klarendalseweg 477-1, Arnhem * 20 min walk from Arnhem Central * 7 min walk from Arnhem Velperpoort * You’ll receive 1 drink token for (beer/wine/soft drinks) and snacks all night! * Find us on the right side of the café at the bar, by the window and garden Bring a smile and join us for an evening where friendships grow, business ideas spark and real-life connections happen. Back to basics, away from screens, meeting face-to-face. Warm regards, Julia

Want to be a speaker? submit your talk to our Call for Presenters!!! https://sessionize.com/azure-cbus-2026/

WQC has weekly Thursday night social nights at the Westerville Java Central. Come and grab a coffee and connect with the community: low stakes, chill environment, and tasty drinks. No registration is required; come as you are.

**Latest Dojo Location!** **Knotty Pine Brewing** 1765 W 3rd Ave, Columbus, OH 43212 We're going to try a new dojo location for a few weeks and see how it works Dojos are informal Python group study sessions where everyone interested in Python gathers to learn about Python, help others with Python, or just hang out. Everyone is welcome from Python beginners to experts. Bringing a laptop is encouraged (we'll have extension cords and power strips). If there's something you want to learn leave a comment on this invite so we can plan ahead. We're looking for speakers for our Monthly Meetups! Fill out the form if you are interested in presenting to the Python Community. https://forms.gle/ehSfUAC2WgR34Crq9

**Kindness Conference 2026** Registration required. Visit [www.kindhelp.org](http://www.kindhelp.org) to register! Imagine a future intentionally shaped by kindness: let's build it together with on **Saturday, July 18th at the Junto Hotel in downtown Columbus!** The function of our conference is to help people develop the skills to build kind community and provide opportunities to increase in-person connection and support in each other’s lives. **This conference is for any of us who are:** · Feeling isolated and lacking community in our current society · Wanting to make a difference in our own lives and the lives of each other · Anyone who is just wishing to create something better! **We will build more kind community by:** · Developing formats for building community-based infrastructure where existing systems are failing that anybody can use · Providing the tools that help people connect in-person and practicing using those tools together · Implementing Universal Design so that no one gets left behind **Opportunities and practical tools we are offering:** · Lunch! · Community-Building Toolkits for people to take home · A chance to build lasting friendships and supportive connections · Opportunities to share referrals, strategies, resources, and the kind of connected support networks many people receive through family, but that those without community and family are often lacking · Ongoing community dinners, free workshops, and other events where people can connect **Participants also have the opportunity to receive CE credits from the Ohio CSWMFT Board.** We are just getting started! This is one of many upcoming events where we can continue making kind community together. **Who else should be here?** Share this opportunity with anyone else who you think might want to build kind community! For more information and to register visit [www.kindhelp.org](http://www.kindhelp.org/). If you would like to help us plan the day, we would love to connect email us at [info@kindhelp.org](mailto:info@kindhelp.org)!

We have moved to guild.host. Look us up there. https://guild.host/events/buckeye-cocoaheads-rcavwd

**How to take control of your subconscious and harness its power!** Join us for an eye-opening lecture where the speaker will break down complex ideas in a clear and practical way. You’ll gain insights into: ✅ The true definition of the subconscious ✅ How it generates unwanted emotions ✅ Its real purpose and function ✅ What determines the pressure it exerts on you And the most important topic: **How do you take control of your subconscious!** But this isn’t just another lecture where you sit and listen passively. It’s interactive and engaging—you can ask questions at any time. 📅 Reserve your spot now! Seats are limited, so don’t wait too long to sign up. Location: 1266 Dublin Rd, Columbus, OH 43215 Hosted by the Hubbard Dianetics Foundation

You can sleep in on the Sesquicentennial (observed), we’re shifting to the following Friday. But join the local UX community for a chat and some biscuits to catch up. If you were in CA for Figma Config, tell us all the lines and you can tell me how I can animate an SVG without coding it by hand, and why I’d even want to. Thanks to the team at Nationwide of supporting the group.