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InfoQ Homepage News Java News Roundup: Generational ZGC, Kotlin 1.5.30, Jakarta EE 10 Release Plan, SpringOne Conference

Java News Roundup: Generational ZGC, Kotlin 1.5.30, Jakarta EE 10 Release Plan, SpringOne Conference

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It was relatively quiet in this week's Java roundup for August 23rd, 2021. Featured news includes JEP 413 having been promoted to Proposed to Target status, the Jakarta EE 10 release plan, work on generational ZGC, Kotlin 1.5.30, MicroProfile Rest Client 3.0-RC1, Hibernate ORM 5.3.22.Final, and the SpringOne conference.


JEP 413, Code Snippets in Java API Documentation, has been promoted from Candidate to Proposed to Target status for JDK 18. This JEP introduces the @snippet tag for Oracle's Standard Doclet, the well-known Java API documentation utility that produces the default HTML-formatted output. The intent is to simplify the inclusion of example source code in API documentation.

JDK 18

Build 12 of the JDK 18 early-access builds was made available this past week featuring updates from Build 11 that include fixes to various issues. More details may be found in the release notes.

For both JDK 17 and JDK 18, developers are encouraged to report bugs via the Java Bug Database.

Jakarta EE 10

Ivar Grimstad, Jakarta EE developer advocate at the Eclipse Foundation, has announced that the Jakarta EE Working Group has approved the Jakarta EE 10 release plan. Less than a year after the release of Jakarta EE 9.1, the first quarter of 2022 has been targeted as the formal release timeframe. As shown in the roadmap below, October 15, 2021 has been defined as the date to initiate release reviews for the specifications currently being updated.

Generational ZGC

Oracle's Z Garbage Collector (ZGC), delivered in JDK 11, is a scalable low-latency garbage collector with goals of:

  • GC pause times not exceeding 10ms.
  • Ability to handle heaps ranging in size from a few 100s of megabytes to many terabytes.
  • Performance overhead that is acceptable for many workloads.

Until now, ZGC has not supported generational collection (the ability to collect short and long-lived objects separately).

Work has been underway by Oracle to support this feature - and three months after creating a branch on the ZGC GitHub repository, a significant number of commits have been added to the zgc_generational branch this past week, paving the way for the arrival of full support for the Generational hypothesis in ZGC in a forthcoming version of Java.


On the road to MicroProfile 5.0, Rest Client 3.0-RC1 was released featuring an update to the Jakarta EE 9 dependencies. Scheduled for fourth quarter 2021 release, developers can expect updates to all eight home-grown APIs: Config, Metrics, Health, Fault Tolerance, JWT Propagation, Rest Client, Open Tracing and Open API.


Hibernate ORM 5.3.22.Final, a maintenance release on the older 5.3 release train has been made available featuring support for JDK 17 and Gradle Java Toolchains. There were also upgrades to ByteBuddy and Javassist to support JDK 17 and the JDK 18 early access builds.


Kotlin 1.5.30, the last incremental release before Kotlin 1.6.0, was made available this past week which includes experimental features that are planned to be stable in Kotlin 1.6.0. These are: sealed when statements that provide a warning if a when statement is not exhaustive; new rules for using and declaring opt-in requirement annotations on different targets; instantiation of annotation classes that allows calling constructors of annotation classes to obtain a resulting instance; and improvements to the Duration and Regex APIs.

Spring Framework

It was a quiet week at Spring, but the good news is that the SpringOne conference will be held on Wednesday-Thursday, September 1-2, 2021. Speakers included in the all-star cast of Java luminaries are: Angie Jones, senior director, developer relations at Applitools; Josh Long, Spring developer advocate at VMware; Trisha Gee, lead Java advocate at JetBrains; Mark Heckler, cloud advocate, Java/JVM languages at Microsoft; Jürgen Höller, Spring Framework project lead at VMware; Billy Korando, Java developer advocate at Oracle; Matt Raible, Java web developer at Okta; Michael Coté, staff technologist at VMware; and Bruce Eckel, president at MindView LLC.

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