International Java Community Conference

looking forward to see you next year

You can watch the JCON2021 sessions on YouTube. We will upload the sessions as they are edited and cut. Make sure to follow us on Twitter and YouTube, so you get notified when we upload a new video.


JCON 2022

Find out about JCON 2022

Watch our keynotes

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Keynote | Java - unlimited in the cloud

Let’s remove the illusion of limits. Step back and rethink. Especially on boundaries that might just be in our head. Microsoft is one of the leaders in distributed Java and even has its own build of OpenJDK. Microsoft’s open-source contributions don't only focus on Java and the OpenJDK, but also Linux, VS Code, TypeScript, Kubernetes, and many more. Many of our tools and approaches are available outside of Microsoft as well. It's an exciting time to use technology to build and deliver whatever you can imagine. We are building value together and welcome everyone to participate and go beyond limits.

Sandra Ahlgrimm

Cloud Developer Advocate, Microsoft

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Keynote | DDD, CQRS, and Event Sourcing, beyond the hype

The demands of software changed dramatically in the last 20 years. Yet, the dominant architectural styles are still based on patterns from the 70s. Although new architectural patterns have emerged, the benefits are often brushed aside. How can we take advantage of these benefits? How do we keep up with the changing non-functional requirements? In this session, we’ll weed out the hype around Event Sourcing. We will look at how DDD, CQRS, and Event Sourcing are combined to form an architectural style that allows us to separate the behavior from the technical details.

Allard Buijze

CTO & Founder, AxonIQ

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Keynote | What Would a Startup Do?

Imagine we quit our jobs and create a startup to create the next killer app. What would we do? Would we start on bare metal, use VMs or containers, stay on-premise, or go to the clouds, or even rent servers on colocation? Would we implement microservices, monoliths, event processors, functions, and should we still use Java?
In this freestyle keynote conversation, I would like to highlight different options and their impact on productivity, maintainability, and event costs.

Adam Bien


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Keynote | In Memory Data Processing with Java

The 4th industrial revolution has begun. An incredible transformation has been running. Communicating edge devices, self-driving cars, drones, robots, combined with AI and ML algorithms, will change our lives more than anything else before in mankind. Data is the gold of this age. However, everything depends on the ability to process these data highly efficiently. High-performance systems will win. Legacy systems will lose. Java provides you incredible performance, just use it.

Markus Kett

CEO, MicroStream & chief editor, JAVAPRO Magazin

Simon Ritter

Deputy CTO, Azul Systems

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Keynote | Quarkus Deep-Dive

This keynote talk dives deep into the internals of Quarkus and explains how its unique architecture makes it different from other frameworks. We will start with an overview of the architecture, then cover how extensions work, and finally go in-depth on the internals of developer productivity features such as continuous testing and Dev Services. By the end of the talk, we will have covered how Quarkus gives you the best of both worlds, with a first-class development experience that still results in small optimized applications.

Stuart Douglas

Senior Principal Software Engineer, Red Hat

About JCON-ONLINE 2021

JCON-ONLINE 2021 is the big international Java community conference organized by the Java User Group Oberpfalz in cooperation with JAVAPRO Magazine. Java is our profession and JCON our passion and a lot of fun. We love to provide Java developers a spectacular 100% live conference that is open to the entire Java- User-Group communities world-wide.

Last year, more than 2,000 participants from 51 countries worldwide have joined the JCON- ONLINE 2020.

The 5th JCON edition is presented as an online live conference for the second time. All sessions will be streamed live and recorded.

Focus on Core Java & Cloud-Native Java

JCON traditionally focuses on Core Java, Serverside Java, APIs and Frameworks because that's what we as Java developers work with every day. However, the main topic will be Java-Cloud-Native and Microservices, because this is the future of Java and must-have for Java developers.


Core Java

Serverside Java

Cloud-Native Java & Microservices


Cloud Platforms & Container


Frameworks & APIs

JVM Languages




Agile & Culture




IDE & Tools

Database Development


JCON Content Board

Richard Fichtner

Founder JUG Oberpfalz, CEO of XDEV Software

Sven Ruppert

Developer Advocate at JFrog

Markus Kett

MicroStream, CEO & JAVAPRO Magazin, Chefredakteur

Matthias Gutheil

branch manager & software architect at Itemis

Sandra Ahlgrimm

Cloud Advocate at Microsoft

Sascha Hesse

Enterprise Architect Cloud Solutions at ALDI Nord SE & Co. oHG

Werner Keil

Director, Creative Arts & Technologies

parallel streams
main topics
live sessions

Featured Speakers 2021

Ivar Grimstad

Java Champion, Jakarta EE Developer Advocate
Eclipse Foundation

Emily Jiang

MicroProfile Guru,
STSM, Liberty Microservice Architect and Advocate

Graeme Rocher

Creator of Grails & Micronaut

Adam Bien

Freelancer, Buchautor, Java EE Experte

Reza Rahman

Principal Program Manager, Java on Azure at Microsoft

Eberhard Wolff


Hendrik Ebbers

Co-Founder & Senior Software Engineer
Karakun AG

Cesar Hernandez

Senior Software Engineer

Grace Jansen

IBM, Developer Advocate

Todd Sharp

Developer Advocate - Cloud And Autonomous DB

Mohamed Taman

Chief Solutions Architect @Effortel, JCP member, Speaker & Author

Mary Grygleski

Senior Developer Advocate at IBM and President of Chicago-JUG

Rory Preddy

Microsoft Senior Cloud Advocate

Diana Cheng

AWS Solutions Architect

Marcus Hellberg

Head of Community at Vaadin

Choose Your Ticket

JUG Pass - 4 Days


  • Access to all conference sessions
  • Q&A with speakers
  • Access to all recorded sessions
  • JUG members only

Full Pass - 4-Days


  • Access to all conference sessions
  • Q&A with speakers
  • Access to all recorded sessions


UCI Cinema Duesseldorf, Germany, 2019

Our Partners 2021

Since the start of JCON, it has been the continuous support from companies and organizations partnering with us to help create events that bring the Java community together. We thank each and every one of our partners for their fantastic support! Please take a few minutes to learn about our partners and let them know you appreciate their support of our community! 


Red Hat is the world’s leading provider of enterprise open source solutions, using a community-powered approach to deliver high-performing Linux, cloud, container, and Kubernetes technologies. Red Hat Developer serves the builders: The problem solvers who create careers with code. Join us to learn more about Quarkus for developers and other related technologies.

Wherever you are in Java—from Java EE/Jakarta EE to Spring and microservices—Microsoft Azure supports your workloads and processes with an abundance of choice. Unload infrastructure hardware and software management to Azure with Azure App Service, Azure Spring Cloud, Azure Kubernetes Service, and fully managed databases so you can focus on writing code. Quickly add services and capabilities like DevOps automation, secrets management, autoscaling, and performance monitoring as your needs expand. We’re excited to see what you build with Azure.

Store and load any Java Object Graph or Subgraphs partially, Relieved of Heavy-weight JPA. Microsecond Response Time. Ultra-High Throughput. Minimum of Latencies. Create Ultra-Fast In-Memory Database Applications & Microservices.

Founded in 2017 in The Netherlands, AxonIQ offers an end-to-end development and infrastructure platform for smoothly evolving Event-Driven Architecture focused on CQRS and Event Sourcing. Our platform known as Axon includes a programming model and a specialized infrastructure to provide enterprise-ready operational support for the programming model - especially for scaling and distributing mission-critical business applications.

Azul, provider of the Java platform for the modern cloud enterprise,is the only company 100% focused on Java. Millions of Java developers, hundreds of millions of devices and the world’s most highly regarded businesses trust Azul to power their applications.

XDEV Software GmbH, based in Weiden/Bavaria, is a German software development company specializing in Java. Among other things, XDEV is the maintainer of various open-source developer tools.

Payara Services is a global open source company and a recognized leader in the creation of innovative infrastructure software for today and tomorrow. We provide industry-leading expertise, products, and services that enable our users to create world-class solutions across a diverse range of industries.

RapidClipse X is a visual Java development environment for the fast and efficient development of individual business applications. Save up to 90% development time.


Java User Group Oberpfalz is an open community to exchange ideas on current topics relating to the application of Java technology in Bavaria / Germany.

We offer contacts and exchanges within the regional Java community and regular talks and discussions on current Java topics.

JAVAPRO is the very first professional magazine for Java which is free of charge.