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London Java Community

The home for those who work with Java and the JVM

What is LJC about?

The LJC is a broad community of technologists and other associates with Java and JVM-related technologies. Although it is based in London, UK – it has some international membership due to its global programmes (such as Adopt a JSR and Adopt OpenJDK). The LJC hosts regular events including casual catch-ups in a cafe, hack days, evening talks, unconferences, workshops, mentoring, demos, a career mentoring by London’s
Java specialists and much more.

The LJC acts as a voice for Java engineers in London UK as well as globally. This includes but is not limited to creating Adoptium, the world’s leading OpenJDK distribution, representing Java developers worldwide on the Java standards body, and contributing towards charitable works.

Upcoming Event

Real-Time Event Aggregation: A No-Code, Scalable Approach

A busy Black Friday can see millions of users hitting your app or website. Keeping track and reacting to real-time events generated in your apps requires a combination of stream processing and low-latency data store. In this talk, we’ll introduce: Declarative Event Aggregation: A No-code solution for handling thousands to millions of events per second YAML Usage: Define aggregations and auto-generate Java code deployed to Hazelcast with a single command. Infrastructure-Free: No need for additional infrastructure; calculated aggregations can enhance machine learning models or serve as context for your LLM-powered assistants.










The next event is coming soon!

Our Initiatives

The LJC has many initiatives, all volunteer lead and founded by our organisers and members. Read about our initiatives below.


The Eclipse Foundation is a non-profit organisation that supports open source software development. It provides a place for developers to collaborate on and innovate open source projects. The Eclipse Foundation also provides services to the Eclipse community, such as IP management, ecosystem development, and marketing.

The LJC has a seat on the JCP and runs the Adopt a JSR programme for Java SE (at OpenJDK), Java ME and Java EE (now Jakarta EE).

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The LJC works on OpenJDK, and co-founded Eclipse Adoptium (the successor to AdoptOpenJDK), the world’s leading FREE OpenJDK distribution!


The LJC is a founding member of –
a new community around building a defacto set of API’s and implementations for Microservices in Java.


The LJC is a founding member of Jakarta EE / EE4J – the new home for Java EE at the Eclipse Foundation.


Sponsor the LJC

The LJC has a multitude of events and global initiatives impacting hundreds of thousands of developers due to the generosity of Recworks, volunteers and key sponsors. You can donate directly or talk to us about a sponsorship package.

Talk to us on Slack

Our LJC Slack group is a vibrant real time community where you can speak with your fellow technologists and world leading experts about topics that matter to you!


Barry Cranford

Founder / Co-organiser

Know More About Us?

Since it’s inception, RecWorks have always invested in and sponsored the London Java Community both in terms of time and money to power the events. Over the years that relationship has now become more official in that for any placement which came through an LJC event, RecWorks now gives a % of all the placements back to the community. 

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