Just my personal anecdote, but I recently had to port the backend of one of my pet projects away from ruby due to performance issues - parsing around 50MB of string in ruby isn't an amazing idea.

So I figured the natural choices there would be go because it's new and in demand, and java because I have a couple years of java se experience.

So, figured, let's evaluate java... and I just failed to comprehend the spring stack just from googled tutorials. There's such a dense layer of magic going on in there, I'd either need to not understand most of my stack, or spend weeks and weeks reading and understanding.