JDK 17: What’s in store for Java 17

Although not due until September, Java 17 has already begun to take shape, with two proposed new features now eyed for the next upgrade to standard Java. A MacOS rendering pipeline proposal was added on February 25. Earlier this month, a proposal of enhanced pseudorandom number generators was targeted for the Java 17 release.

Features filed as part of OpenJDK’s Java Development Kit (JDK) 17 include: 

• A new rendering pipeline for MacOS, using the Apple Metal API as an alternative to the existing pipeline that uses the deprecated OpenGL API. This proposal is intended to provide a fully functional rendering pipeline for the Java 2D API that uses the MacOS Metal framework and be ready in the event Apple removes the OpenGL API from a future version of MacOS. The pipeline is intended to have functional parity with the existing OpenGL pipeline, with performance as good or better in select applications and benchmarks. A clean architecture would be created that fits into the current Java 2D model. The pipeline would coexist with the OpenGL pipeline until obsolete. It is not a goal of the proposal to add any new Java or JDK APIs.
• Enhanced pseudo-random number generators that would provide new interface types and implementations for pseudorandom number generators (PRNGs) including jumpable PRNGs and an additional class of splittable PRNG algorithms (LXM). A new interface, RandomGenerator, would supply a uniform API for all existing and new PRNGs. Four specialized RandomGenerator interfaces would be provided. Motivating the plan is a focus on multiple areas for improvement in the area of pseudorandom number generation in Java. The effort does not call for providing implementations of numerous other PRNG algorithms. But three common algorithms have been added that already are widely deployed in other programming language environments. Goals of the plan include:
  • Making it easier to use various PRNG algorithms interchangeably in applications.
  • Improved support for stream-based programming, providing streams of PRNG objects.
  • Elimination of code duplication in existing PRNG classes.
  • Preservation of existing behavior of class java.util.Random.

In coming months, more features will be proposed for JDK 17. Possibilities include a foreign linker API, a vector API, and a foreign-memory access API, all of which are currently in an incubator stage in the JDK 16 release due March 16. Sealed classes, in a second preview in JDK 16, could become generally available in JDK 17.

Early-access open source builds of JDK 17 can be found at jdk.java.net. JDK 17 is slated to be the next long-term-support (LTS) release of Java, meaning it would receive multiple years of support; other Java releases, serving as feature releases, are supported for just six months.

LTS releases arrive every three years. The last LTS release, JDK 11, was published in September 2018. New releases of Java arrive every six months. The current release line of standard Java is JDK 15.