This thread is about a course on Advanced Programming in the Unix Environment. After looking at the content of the course, I'd argue that there's an implied "Systems" between "Advanced" and "Programming". (Indeed, this course is taught using the famous book whose title it borrows, and is heavily C oriented.)

Java is neither common nor especially well suited for the topic of this course.

So while I share your opinion on IntelliJ as a Java IDE, I would not recommend it for UNIX systems programming. And even the IntelliJ-derived Clion, which is (IMO) decent for that, leaves something to be desired when it comes to learning the topic.