Brian Goetz's recent message Welcome to Amber! introduces Project Amber (part of OpenJDK and proposed originally in January). Goetz opens the message with the introduction, "Welcome to Project Amber, our incubation ground for selected productivity-oriented Java language JEPs." Goetz reiterates that Project Amber is not for discussing ideas for arbitrary potential new language features, but rather is for collecting new language features for which a JDK Enhancement Proposal (JEP) already exists ("let's keep the focus on the specific features that have been adopted").
Three JEPs are already associated with Project Amber: JEP 286 ("Local-Variable Type Inference"), JEP 301 ("Enhanced Enums"), and JEP 302 ("Lambda Leftovers"). Goetz also writes that "the 'data classes' and 'pattern matching' features, already discussed publicly are intended to be adopted by Amber when we're ready to propose JEPs on them."
I was enthusiastic about the announcement of Project Coin with JDK 7 and have really enjoyed using its features. I feel a similar excitement about Project Amber and look forward to using its features on a regular basis. Nicolai Parlog has written that Project Amber Will Revolutionize Java.