I’ve continued to work with JupyterHub since my last post, and have made significant progress towards my overall goal of creating a real system for developing a programming course.

The first development was to recreate my work to date on a new server: Ubuntu 18.04 Server, as opposed to Desktop, which I had been using. I also moved this server to VirtualBox (now V6) on a different machine. The new machine acts as a file server and has capacity to spare, plus stays on “as a server” all the time.

Installing Ubuntu 18.04 Server on the machine was not difficult, and following my scripts I was able to create JupyterHub on the new server, with full encryption and networked through “huntrods.com”. I also recreated the various demo logins to allow me to share this work with other colleagues.

I finished developing “Unit 0” for my Java programming course, as well as exploring other resources such as using it for my Network Java Programming course. There were some issues, but most of the programs work.

I also found some significant shortcomings in SciJava, which I contacted the developers for more documentation. Their response was “move to BeakerX, as it has a full Java implmentation”. They also informed me that SciJava might be End-Of-Life soon, which would be unfortunate.

However, I installed BeakerX according to guidelines from a developer on my single-user Ubuntu Desktop. It worked, so I then tried installing it on the Ubuntu Server. After one set of instructions failed, I reverted to the method that worked for many of the packages, and it worked.

I now have a full-featured Java running on JupyterHub under BeakerX. There is one outstanding issue that affects both BeakerX-Java as well as SciJava: neither will accept user input from the keyboard.

Another limit on BeakerX-Java is that it won’t run fragments of code that aren’t real Java. Example: SciJava will evaluate “10+23” and output “33”. BeakerX-Java gives an error as would happen with “real” Java (which is what BeakerX has).

It turns out (from the developer) that SciJava is really a Java+Groovy hybrid, which is great for what I’d been doing, but isn’t really “real” Java.

Either I modify my Unit 0, or go with the SciJava in some notebooks and BeakerX-Java in others.

However, it’s great to have full-blown Java available in my notebooks.