Before Julia I used to code in Java, and Java has static arrays (immutable size).

I know for sure that static arrays are way faster than dynamic ones, so how can I use they in pure Julia?

I found a package called “StaticArrays” and it says that StaticArrays can perform up to 25x faster than dynamic, so why does Julia don’t use this as a core feature?

As a bonus question: can you people recommend me packages for performance and for adding some important tools that Julia doesn’t offer in the standard library, like data structures, functions and so on. In special mathematical tools for optimization on algorithms.

Thanks!!