https://adtmag.com/articles/2019/12/16/valhalla-update.aspx

Brian Goetz, Oracle's Java language architect, has posted a "State of Valhalla" update to the OpenJDK mailing list on the progress to date on this now five-year-old effort to bring more flexible flattened data types to JVM-based languages and to bring the Java programming model back in line with the performance characteristics of modern hardware.

Over the past five years, Goetz and company have built five prototypes to understand different aspects of the problems Valhalla seeks to remedy.