There's a contradiction there I grant, but by "frictionless" I mean I didn't fight with the environment at all.

I'd contrast that to the Java course where you learn the strange dialect of "single file Java" where you might write a single main() method or write only static methods. If you need to you can write as many classes in a single file, but only one can be public, unless they are inner methods. You probably don't need public methods.

It's a strange enough world and distant from ordinary Java coding, yet kinda fun and helpful for mastering whiteboard interviews.