I mentioned this uses preview features twice in the first comment regarding this, so I don’t know why you’re "ah ha"ing. Also you don’t need to read the technical document, I’ve quoted the entirety of the relevant text. I provided it as a citation.
You seem confused about preview features. It’s not a switchable mode to reduce boiler plate. I find the name very clear, but here is more information. From JEP-12
A preview feature is a new feature of the Java language, Java Virtual Machine, or Java SE API that is fully specified, fully implemented, and yet impermanent. It is available in a JDK feature release to provoke developer feedback based on real world use; this may lead to it becoming permanent in a future Java SE Platform.
As an example, JDK 17 added pattern matching for switch statements as a preview, and by JDK 21 it was added as a full fledged feature that doesn’t require usage of the enable preview flag. Presumably in some future release of Java this feature will not require the usage of a flag.
It is pretty late for me. Sorry. And thank you for your patience. Repeating it three times helped.
I will be interesting to find out if the resulting binary is the same or not and what’s possible once it matured.