
Applied AI Researcher, Speaker, DevRel expert. Java Champion. VP of AI Research @vaadin
California, USA
Joined November 2008
- Tweets7K
- Following728
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Where does full-stack Java go next?
Vaadin Create 2026, Barcelona, Oct 27–28: 2 days, 3 tracks, 20+ speakers including Josh Long.
Trailer: youtube.com/watch?v=bfydXyAe…
Tickets: vaadin.com/vaadin-create-202…
Marcus Hellberg retweeted
Vaadin is AI native. And it's an amazing fit for Spec-Driven Development.
Vaadin 25.3 is built for AI coding agents that work on Java UIs:
✅ A dev loop that works like an IDE for your agent
✅ A self-hosted MCP server with the full Java API (even air-gapped)
✅ Browserless tests, so the agent gets fast feedback without a browser
✅ An Observability Kit insights endpoint your agent can read
Why does this matter for Spec-Driven Development?
With Vaadin, the UI is plain Java. No JavaScript, no REST layer, no second tech stack. The agent works in one language and one codebase. That makes it much easier to go from the spec to running code, and to check with tests that the code still matches the spec.
Specs give the direction. Vaadin keeps the path short.
🎥 Watch the 5-minute overview: youtube.com/watch?v=WnkI6xA9…
📣 Want to see it live? Next week I speak at Vaadin Create 2026 in Barcelona (27-28 October): "Spec-Driven Development - Why Vaadin Is the Perfect Fit"
AI can generate code. The hard part is to keep it aligned with the system you really want to build. I will show how specifications and architectural guardrails guide a full-stack Java application while it grows.
See you in Barcelona! 🇪🇸
vaadin.com/vaadin-create-202…
#Vaadin #Java #SpecDrivenDevelopment #AIUP #AI #VaadinCreate
Marcus Hellberg retweeted
How fast can your AI agent find out that the code it just wrote is correct?
This question matters more than ever. Agents write code in seconds, but browser-based tests take minutes and often fail for the wrong reasons: timing, waits, flaky selectors.
Vaadin Browserless Testing changes this. The whole flow runs in one JVM: the view, the validation, the service, the jOOQ query. Tests run in milliseconds and are deterministic. When a test fails, the code is wrong. Not the timing, not the network.
Bonus: JaCoCo sees the UI code too, so you get one honest coverage number for the entire application.
In my new blog post I explain why this is a game changer for AI generated web applications, and why the classic SPA architecture cannot match it:
martinelli.ch/why-vaadin-bro…
#Vaadin #Java #SpringBoot #jOOQ #Testing #AI
Marcus Hellberg retweeted
A small experiment with Claude Code:
Hotel room search, built twice.
1) Vaadin + Spring Boot + jOOQ + Testcontainers + PostgreSQL: 3 minutes.
2) Angular + Python + DynamoDB: about 5x longer.
Why the gap? One stack is one language, one runtime, and a clear data model. The other is two ecosystems, two languages, and design decisions that need to be made up front.
Choose your tech stack wisely.
Vaadin 25.1 brings reactive state management to Java—define your state once, and your UI stays in sync automatically.
#Java #FullStack #WebDev #ReactiveProgramming
Marcus Hellberg retweeted
Many know that in its early days @vaadin was called Millstone. Did you know that for a split-second, it was called Enably?
Marcus Hellberg retweeted
Vaadin 25.0 has landed! 🛬
✨ New "Aura" theme & native CSS styling
☕ #Java 21 + Spring Boot 4 support
🚀 50% faster dev-mode startup
📦 Production-ready builds by default
📉 30% fewer dependencies
Check it out: vaadin.com/blog/vaadin-25-0-…
Marcus Hellberg retweeted
Want to add a filter to a @vaadin Grid – in Java only?
Drew shared a nice example showing how simple it can be.
🔗 Code:
github.com/drewharvey/vaadin…
Great for dashboards & CRUD apps.
#Vaadin #Java #WebDev
Marcus Hellberg retweeted
Today's #JCON Content Board Spotlight: @marcushellberg (Vaadin)
Another #JavaChampion within our board who has over 20 years of experience in combining modern web #technologies and #Java
Whether hiking or exploring the next #AI integration, he is fully committed.
Join #JCON2026 at 2026.europe.jcon.one/
Marcus Hellberg retweeted

LangChain4j@langchain4j26 Nov 2025
🇩🇪
GermanyConnected via Germany Android AppAccount-level information, not a live location or per-post device.
#LangChain4j 1.9.0 is out! 🎉
github.com/langchain4j/langc…
Marcus Hellberg retweeted
🟦 Full-stack Web Apps, 100% Java with @marcushellberg (Vaadin).
One language. One stack. As Odin intended ⚡
👉 jfokus.se/
#Jfokus #DeveloperConference #Java #Vaadin #SpringBoot #Fullstack #WebDevelopment
Marcus Hellberg retweeted
Spring Boot 4 is now available 🎉🤩
spring.io/blog/2025/11/20/sp…
Marcus Hellberg retweeted
As requested, I will do a live demo on how I use the AI Unified Process aiup.dev
Join my live stream next week on Tuesday, November 18th, at 4 pm CET.
Prepare your questions!
youtube.com/watch?v=jwPBHVNv…
Marcus Hellberg retweeted
IntelliJ IDEA + Qoder + Vaadin + Vaadin MCP Server: just a simple prompt to generate code for account and login support for entire app.
Marcus Hellberg retweeted
Spring Framework 7 is GA!
spring.io/blog/2025/11/13/sp…
Marcus Hellberg retweeted
🚀 Spring AI 1.1.0 GA Released
🔧 Better MCP Integration ... 🔐MCP OAuth2 server protection 🔄 Recursive Advisors ...📦 Developer Experience: ... Over 850+ commits
Kudos to the entire Spring AI community! 🙌
Find more: spring.io/blog/2025/11/12/sp…
Marcus Hellberg retweeted
👾Vaadin Tutorial for Beginners: Beautiful UIs in Pure Java
My new step-by-step tutorial on using @vaadin with @springboot to build awesome UIs. Create a login page, filtered search, and update form in just 15 minutes. No HTML or JS needed!
youtu.be/67oJxPRa3Mg
Marcus Hellberg retweeted
Excited to be speaking at @vaadin Create 2025! 🚀
📅 Day 1: "Spring AI & MCP for all things AI" talk
🔧 Day 2: Hands-on lab with @marcushellberg
Discover how JVM rules the AI world! vaadin.com/vaadin-create-202…
@SpringAICentral @MCP_Community
Marcus Hellberg retweeted
Replying to @marcushellberg
@marcushellberg just delivered “Full-stack web apps, 100% Java” at #JCON USA @ #IBM #TechXchange. A crisp live-coding tour of #OpenLiberty + #Vaadin Flow—from persistence and external services to a good-looking UI—all in #Java!
Bonus: it’s his birthday today 🎂 If you’re onsite, catch him in the hallway track and wish him well!
#JCONUSA2025
Marcus Hellberg retweeted
🍃 Real-World AI Patterns with Spring AI and Vaadin by @marcushellberg /@vitalethomas @ Spring I/O 2025
▶️ Video: youtu.be/cLWFu33kM3E
🔗 Slides: speakerdeck.com/thomasvitale… #springio25



















