After Project Valhalla's "Value Types/Objects," the language feature I am perhaps the most excited to see come to Java is Project Amber's "Data Classes" (AKA "Records"). I wrote the post "Updates on Records (Data Classes for Java)" about this time last year and use this post to provide an update on my understanding of where the "records" proposal is now.
A good starting point for the current state of the "records" design work is Brian Goetz's February 2019 version of "Data Classes and Sealed Types for Java." In addition to providing background on the usefulness of "plain data carriers" being implemented with less overhead than with traditional Java classes and summarizing design decisions related to achieving that goal, this post also introduces noted Java developer personas Algebraic Annie, Boilerplate Billy, JavaBean Jerry, POJO Patty, Tuple Tommy, and Values Victor.