Hot on the heels of Oracle’s release of the Java 21 platform, Microsoft now is offering its own build of the open source OpenJDK 21, at no cost.

Available from learn.microsoft.com as of September 28, the Microsoft Build of OpenJDK 21 is available for Linux, Windows, and Mac. In elaborating on Oracle’s publishing of Java 21, which occurred on September 19, Microsoft said the release contains features that set it apart from previous Java versions. The company highlighted new capabilities such as simplified Java learning for beginners, with a preview of unnamed classes and instance methods, as well as unnamed patterns and variables; a preview of the Generational ZGC (Z Garbage Collector) for enhanced performance; and virtual threads for high-throughput concurrent applications.

Microsoft Build for OpenJDK 21 binaries will receive long-term support from Microsoft; LTS releases receive quarterly updates via microsoft.com/openjdk. These updates are free of charge. Oracle designated Java 21, or Java Development Kit 21, as a long-term support release, to receive at least eight years of support. Microsoft also offers builds of OpenJDK for JDK 17 and JDK 11, both also long-term support releases. Microsoft initially unveiled Microsoft Build of OpenJDK in April 2021.

Microsoft also said that JDK 21 soon would be available across Azure PaaS cloud services. The company is offering a proof-of-concept launcher, called Windows Container JVM Launcher, to run Java inside Windows Containers in process isolation mode.

In addition, Microsoft announced a new release of Semantic Kernel for Java, version 0.2.9, which it described as being an alpha state. Semantic Kernel is lightweight SDK for integrating large language models for generative AI with conventional programming languages. The new library will help developers enhance Java applications with augmented intelligence via idiomatic integration of large language models.