Java Development Kit 17 and Java 17 are now generally available. JDK 17 was announced by the Open JDK group and Oracle released the new version under a commercial license for those using the Oracle JDK release as part of an Oracle product or service, or for those who want to be able to get commercial support.
Java 17 is an LTS (Long Term Support) version and Oracle says Oracle JDK 17 and future JDK releases are provided under a free-to-use license until a full year after the next LTS release. Oracle will also continue providing Oracle OpenJDK releases under the open-source General Public License (GPL), as it has since 2017.
Oracle says the new release delivers thousands of performance, stability, and security updates, as well as 14 JEPs (JDK Enhancement Proposals) to improve the Java language and platform. Java 17 is the latest long-term support (LTS) release, following on from the previous JDK 11 LTS released three years ago.
The language improvements start with the addition of support for sealed classes. Sealed classes and interfaces restrict which other classes or interfaces can extend or implement them. The development is part of Project Amber, which is used to explore and incubate smaller, productivity-oriented Java language features.
Other JEPs mainly involve updates and Improvements to libraries. This release has reincorporated strict floating point semantics. Back in Java 1.2, small variances in floating point strict semantics were allowed by default to accommodate limitations of then-current hardware architectures. Because this is no longer helpful or necessary, the variances have been removed.
There's also an enhanced pseudo-random number generator that provides new interface types and implementations for pseudorandom number generators. The developers say the change improves the interoperability of different generators and makes it easy to request an algorithm based on requirements rather than hard coding a specific implementation.
Other improvements include support for MacOS, with a new macOS rendering pipeline and a macOS aArch64 port that ports the JDK to the macOS/AArch64 platform. This port will allow Java applications to run natively on the new Arm 64-based Apple Silicon computers.
