We give onsite candidates affordances to install any environment that makes them feel comfortable, or to allow them to bring their own machines. The interview machines get wiped on a regular cadence, so installing packages is no big deal.

If candidates send us a list of the software they want beforehand, we usually try to set it up for them in advance. If not, it's fine for the schedule to run over a bit for them to tweak things as they like.

Interviews are stressful enough. We want everything working in a candidate's favor so they can do their best.

I hope he's now writing CRUD apps in J2EE.