Not so much a unification, as the new constructs sort of enhance and retrofit current primitives types. These new primitives are "class instances that lack object identity and can be stored and passed directly, without object headers or indirections".

It will allow (almost) direct control over data layout. At least make it so that it is cache/prefetch/SIMD friendly.

Here is the JEP: https://openjdk.java.net/jeps/401