I have no idea what happened. When I was updating my books for Java 10, maybe 6 months ago everything worked perfectly. Now I'm updating for Java 11 and I cannot get the Java code to work. I'm getting an error like this:

java.lang.UnsupportedClassVersionError: path/to/myfile has been compiled by a more recent version of the Java Runtime (class file version 53.0), this version of the Java Runtime only recognizes class file versions up to 52.0 (unable to load class [path/to/myfile])

The code was running in Java 9; which was the latest when I started writing my books, but is ancient now. What is going on? Did an IntelliJ update change things? Or is Maven pulling in updated libraries w/o my input?

Honestly, I'm not quite sure. I Was able to fix this by changing my windows envirnment variables. I had to point JAVA_HOME and JRE_HOME to my Java 9 install. They were pointed at my Java 8 install. I'm sure I didn't downgrade my Java settings for any reason, so I suspect that some update to IntelliJ must have started using system settings instead of its own internal settings.

By the time you read this, my new Angular 11 books will be out.