I made some progress!
First, Java 1.8 was already installed. I installed my own copy in /opt but when I ran update-alternatives --config, I saw it was already loaded elsewhere so I abandoned my /opt installation and just pointed the system at the existing 1.8.
$ sudo update-alternatives --config javac
$ sudo update-alternatives --config java
Then I followed this post and created a librxtxSerial.so symlink.
At that point, my insteon.log file was generating tons of output. My dimmer still wasn’t responding though.
I grabbed the latest stable binding from here. I hope that is the right place!
I shut down the openhab service, removed the 1.8 binding I was using, and swapped in the new binding I downloaded. I started up the openhab service, went to my site, and still nothing.
Here is a dump of the service starting. I tried the site but the dimmer slider control still did not move. I also hit some buttons on the dimmer as a sanity check. I’m not sure what to look for but it looks like the binding is talking to the modem as it was able to download the modem db and display the manual links I had made previously.
Also, I got Insteon Terminal to compile and run but haven’t looked at it in depth yet.