The London Java Community for the Docklands

Apr 12 2016

Faster Ruby and JS with Graal/Truffle and Neo4J with Clojure

2016, chris seaton, clojure, graal, java, javascript, jruby, mark needham, neo4j, ruby, truffle

We are pleased to bring you the tenth event of the Docklands.LJC; a group within the main London Java Community that focuses on the developer community in and around Docklands on the second Tuesday of each month. Our speakers this month are Chris Seaton and Mark Needham.

Chris Seaton - Faster Ruby, JS and other languages using Graal and Truffle

Many people run languages other than Java on the JVM, but the performance of these languages often lags well behind Java and native implementations of the same languages.

Oracle Labs is researching a new way to improve the performance of both Java and other languages on the JVM. We are developing Graal, a new JIT compiler written in Java, making development on it easier and so enabling new research into optimisations, and Truffle, a framework for implementing languages that uses Graal.

Our implementation of Ruby using these technologies is an order of magnitude faster than any other implementation of Ruby, on real-world code, and our implementation of JavaScript is competitive with Google’s V8.

Most exciting is the possibility of interoperability between languages such as Java, Python, Ruby, R and JavaScript, while also achieving this very high performance.

The presentation and video recorded from the event are now available on InfoQ.

Mark Needham - Using Clojure and Neo4j to build a meetup recommendation engine

In this talk Mark will show how to build a meetup recommendation engine using the graph database Neo4j and Clojure. We’ll build up a solution from scratch which combines content based and collaborative filtering using Cypher - the graph query language - to find patterns in the graph and Clojure to do the data manipulation.

The presentation and video recorded from the event are displayed below:


Dr Chris Seaton is a Research Manager at the Virtual Machine Group in Oracle Labs, where he leads the work to implement Ruby using the next generation of Java Virtual Machine technology, and other projects.

In his spare time he used to develop an award winning medical app that is the first app regulated as a medical device in the UK, and ran a consultancy to help clients such as the NHS to develop revolutionary medical software.

Mark Needham is a graph advocate and field engineer for Neo Technology, the company behind the Neo4j graph database. As a field engineer, Mark helps customers embrace graph data and Neo4j by building sophisticated solutions to challenging data problems.Mark also organises the Neo4J London meetup and blogs at

This event is being hosted by Credit Suisse in London. Sign-up information is available at