Scala compiler : wrapper to primitive

Question
1

From a book on Scala:
“In Scala, there is no need for wrapper types. It is the job of the Scala compiler to convert between primitive types and wrappers. For example, if you make an array of Int, you get an int[] array in the virtual machine.”

But why do we need to convert to int[] array?

2

Why does who need to convert what to int[] when?

3

An array of boxes types is far less performant than a primitive array

4

Array[Int] (Scala) and int[] (Java) are precisely the same type. Both at compile time, and at runtime. No boxing.