How do I get IntelliJ to recognize gradle generated sources dir?

Question

So I have an XJC javaExec that spins like a top but IntelliJ doesn\'t recognize the generated output despite having marked generated-src/java as such. Do I need to

Answer 1

in 2020 you probably did not refresh the project in IDEA

because it actually works oob.

30 mins of reading outdated solutions :(