http://cr.openjdk.java.net/~briangoetz/amber/datum.html http://cr.openjdk.java.net/~briangoetz/amber/datum.html There you can read about algebraic data types i

http://cr.openjdk.java.net/~briangoetz/amber/datum.html http://cr.openjdk.java.net/~briangoetz/amber/datum.html There you can read about algebraic data types in java, in Java 14 you get preview for records in Java 15 probably you'll get preview for sealed types - they were developed together for some time, only recently there was a split.