JDK 21 Forked From Mainline For What Will Be The Next Java LTS Release
With being forked from mainline, the feature set of OpenJDK 21 is effectively frozen now and the coding is now focused on bug fixing and any approved late enhancements. The initial release candidate of JDK 21 is due in August, a second release candidate in late August, and the current GA target for JDK 21 is 19 September.
JDK 21 is bringing Virtual Threads as a lightweight threading solution, string templates in preview form, generational behavior for the Z Garbage Collector, the third preview of the Java Foreign Function & Memory API, the latest iteration of the work on Java's Vector API to make use of modern CPU architecture features, and structured concurrency in preview form.
More details on the new features coming with JDK 21 and the planned schedule for this next reference Java software release can be found on OpenJDK.org.