Java Development Kit (JDK) 21, due September 19 as the next long-term support (LTS) release of Oracle’s standard Java implementation, has reached the release candidate (RC) stage. Java 21 will have 15 features, as a previously proposed 16th feature, the experimental Shenandoah garbage collector, was dropped in June.
The 15 features that made the final cut range from previews of string templates and structured concurrency to virtual threads to a key encapsulation mechanism (KEM) API. JDK 21 reached a second rampdown phase July 20, following an initial rampdown phase that began June 8. The release candidate stage, which began August 10, runs concurrently with the second rampdown stage. A second RC is due August 24.
