I've heard this "more productive" refrain countless times, but I have yet to see it in reality. I would love to be made aware of how exactly Java doesn't allow

I've heard this "more productive" refrain countless times, but I have yet to see it in reality. I would love to be made aware of how exactly Java doesn't allow one to pivot easily. That said, we have been at it for 5 years now, so it would be a stretch to call us a startup, but we use Java for 90% of our platform codebase, with Ruby acting as a glue.