Java - but done so horribly even the devil would be aghast.

There were thousands of threads, murmuring an incessant hum fully occupying a few cores when absolutely nothing was happening. Over 20GB RAM actively used at idle.

I think booting the application took almost half an hour at one point, using a local SSD.

I’m fairly certain at no point in my career could I ever have replicated such a monstrosity.