I think the last new instruction the JVM added was invokedynamic like 10 years ago. I believe they did it so lambdas could be called efficiently. Polymorphic incline cache and stuff.
But the JVM has grown more complex in other ways. The way to force simd instructions is pretty wild, for example.
I don't know enough to call it a mess or not. It works though.
I don't believe Prometheus supports geospatial data. Two minutes of googling though, so I could be wrong.