Yeah, what he said... sort of. First we tried just smushing everything into JRuby, but that was a mess. We then split the app into a bunch of services, instead

Yeah, what he said... sort of. First we tried just smushing everything into JRuby, but that was a mess. We then split the app into a bunch of services, instead of one monolithic rails beast. Each new service is a simple java app. It was a gradual process, taking about 7 months.