Last Friday we had guests from Belgium and the Netherlands joining us in Cologne. Maarten-Jan Kallen from BeDataDriven came from The Hague to introduce us to Renjin, and the guys from DataCamp in Leuven, namely Jonathan, Martijn and Dieter, gave an overview of their new online interactive training platform. Renjin Maarten-Jan gave a fascinating introduction to Renjin, an R interpreter in the Java virtual machine (JVM). Why?