I don't use IDEA for Java work, I use it because it's the only IntelliJ platform app that supports "all" languages (or at least all the languages I care about),

I don't use IDEA for Java work, I use it because it's the only IntelliJ platform app that supports "all" languages (or at least all the languages I care about), but sure let's go with your examples above. If you're hiring someone to do java work, who has no experience of jar files, or java build tools, them not being able to use IDEA is the least of your concern. This is like saying "on the first day of work as a carpenter, we send all new hires on an intensive nail-gun training course, because they probably don't know how to use a circular saw, or even what the pointy end of a nail is for" I don't know what schools teach these days, but all the classes I had (one of which, coincidentally enough was java) specifically made us not use an IDE - we had to use a text editor for all practical work. Once you know what you actually need/want to do, using a different tool to achieve it is generally not a complex task. If someone knows how to use a screw driver, they don't need comprehensive training to then use an electric drill/driver to put a screw in. If they don't know how to use a screw driver, giving them a drill/driver to learn, is a fucking terrible idea.