It would be nice if OpenJDK came with some kind of pre-configured IntelliJ project.
Note that something similar for langtools and the NetBeans IDE exists already.

Since there is platform specific code, and code generated into a platform / spec
specific location, it is not practicable to create a static standard project. It is
also desirable for the project to support a subset of OpenJDK modules, for those
not intending to work on all modules.