I talked in the morning with Derek. Here is a brief description of them:
I mention to him that I created some javadoc here with 'mvn site' to dig some classes and I notice that there wasn't no class diagram there, I said this way because I usually put an umlgraph plugin which generate it using the classes of the project and we can specify some configuration of the generated diagram. It is pretty simple to setup (just need to add a new reporting, an example http://www.beabetterdeveloper.com/2013/03/automated-class-diagrams-using-maven.html ), I think the only overhead is a little more time to generate the javadocs and it also needs to install a librry (graphviz) in the machine before hand. Well, if you liked it, we could implement it on the jenkins server.
I also found another interesting eclipse plugin that might be very useful for debugging some hard issue. It is called Diver ( http://eclipsediver.wordpress.com/tutorials/https://www.youtube.com/watch?v=FzMl4Zu2tps ). It can record a debug session (you inform when to start and to stop) and filter between different recorded debug sessions, making only the new methods (with their state) be shown. It can display that using an sequence diagram (maybe also useful to generate a more realistic diagram from how Lightblue works to explain to new team member)
I like class diagrams, I did something earlier on locally to generate them to help understand the class dependencies. +1 to putting it on jenkins and to publishing javadocs somewhere. I've created a jenkins node on openshift in lightblue namespace. Email me your login and I can add you as an admin so you can get at the jenkins credentials etc.