I'm sorry you spent time trying to get started with Gemini, because it's our internal framework that isn't released yet. That would have been frustrating for you!
From our "Motivations" section: http://www.techempower.com/benchmarks/#section=motivation "Why include this Gemini framework I've never heard of?" We have included our in-house Java web framework, Gemini, in our tests. We've done so because it's of interest to us. You can consider it a stand-in for any relatively lightweight minimal-locking Java framework. While we're proud of how it performs among the well-established field, this exercise is not about Gemini. We routinely use other frameworks on client projects and we want this data to inform our recommendations for new projects.