The project was announced in July 2014 and is an experimental effort by Oracle, led by engineer Brian Goetz.
Project Valhalla has begun in the experimental stages, with an inaugural announcement & early draft initial proposals.
Providing primitive class declarations from them removes much of this special-casing, leading to a more elegant and easy to understand type system.
'Value Type' features and 'Generic specialization' (when applied to lists or collections) reduce memory usage, but more importantly avoid pointer indirection which typically causes a cache miss.
[8][9] Instead of a list or array of object references, pointing to data values scattered throughout memory, Project Valhalla enhancements will enable list or array values to potentially be laid out linearly—without indirection—as a consecutive block of memory.
These would no longer require object identity and associated memory/ pointer overheads, though would be able to assume a 'boxed' form for compatibility.