JDK 17: What’s in store for Java 17

A new rendering pipeline for MacOS and a uniform API for pseudo random number generators are proposed for the Java long-term support release due in September.

JDK 17: What’s in store for Java 17
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Although not due until September, Java 17 has already begun to take shape, with four proposed new features now being considered for the upgrade to standard Java. The latest additions, as of March 30, include a MacOS/AArch64 port and deprecation of the Applet API. These follow February proposals for a new MacOS rendering pipeline and enhanced pseudorandom number generators.

Java Development Kit (JDK) 17 will be a long-term-support (LTS) release, with extended support from Oracle expected for several years.

Features filed as part of OpenJDK’s JDK 17 include: 

  • Porting the JDK to MacOS/AArch64 in response to Apple’s plan to transition its Macintosh computers from x64 to AArch64. An AArch64 port for Java already exists for Linux and work is underway for Windows. Java builders expect to reuse existing AArch64 code from these ports by employing conditional compilation, as is the norm in ports of the JDK, to accommodate differences in low-level conventions such as the application binary interface and the set of reserved processor registers. Changes for MacOS/AArch64 risk breaking the existing Linux/AArch64, Windows/AArch64, and MacOS/x64 ports, but the risk will be reduced through pre-integration testing.
  • Deprecating the Applet API for removal. This API is essentially irrelevant, since all web browser vendors either have removed support for Java browser plug-ins or have announced plans to do so. The Applet API previously was deprecated, but not for removal, in Java 9 in September 2017.
  • 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.

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