JEP draft: Universal Generics

[Dan Smith]

Please see this JEP draft:

http://openjdk.java.net/jeps/8261529

This is the third anticipated piece in our initial suite of Valhalla preview features (along with JEPs 401 and 402). It's also the first step in the revised generics story, to be followed up in the future with JVM enhancements for better performance (including species & type restrictions).

This is entirely a language enhancement, and will be experienced by developers as a number of new warnings for generic classes and methods. Addressing the warnings makes generic APIs interoperate smoothly with primitive value types and prepares them for the future JVM enhancements.