What did not work was installing the default JDK 11 .deb file from:
https://www.oracle.com/technetwork/java/javase/downloads/jdk11-downloads-5066655.html
My interpretation is that this file creates a JVM folder in /usr/lib/jvm but no JDK folder that IntelliJ can recognize.
What did work is this tutorial:
https://community.linuxmint.com/tutorial/view/1372
I will summarize.
1> Remove any openjdk installations you might have:
$ sudo apt update && sudo apt remove openjdk-*
$ sudo apt autoremove # optional removal of leftover crap
..
2> Get jdk-8u201-linux-x64.tar.gz from:
https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
3> Make a new java directory in /opt:
$ sudo mkdir -p /opt/java
..
4> Move and extract the jdk-8u201-linux-x64.tar.gz file:
$ sudo mv ~/Downloads/jdk-8u201-linux-x64.tar.gz /opt/java/
$ sudo tar zxvf jdk-8u201-linux-x64.tar.gz
..
5> Make the new Java JDK system default:
$ sudo update-alternatives --install "/usr/bin/java" "java" "/opt/java/jdk1.8.0_201/bin/java" 1
$ sudo update-alternatives --set java /opt/java/jdk1.8.0_201/bin/java
Done!
$ java -version
java version "1.8.0_201"
Java(TM) SE Runtime Environment (build 1.8.0_201-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.201-b09, mixed mode)
..
Workspace Screenshot:
