This note illustrates how to setup JetBrains IntelliJ IDEA for JOSM development.
- Get the source
- Add project from existing source
- Project Settings / Project:

- Project Settings / Modules:

- Project Settings / Modules: add+configure IvyIDEA

- Tools / Ivy / Resolve for All Modules:

- Configure Ant:

- Run the following Ant tasks:

- Run
org.openstreetmap.josm.gui.MainApplication:
This is of great help, and should (mostly) replace what is currently on
https://josm.openstreetmap.de/wiki/DevelopersGuide/CompilingUsingIntelliJ
I was puzzled for a moment about the /tmp/josm/... paths, but it's probably just where you checked out JOSM temporarily to build make this howto. Maybe use a more ordinary location, e.g. /home/someuser/josm
Maybe you also want to show that running (specific) unit tests is also very easy using this setup.