JDK 19: The new features in Java 19


Java Improvement Kit 19, thanks this September, is now function-total, getting just attained an initial rampdown section. 7 capabilities concentrate on the launch such as structured concurrency, record patterns, a preview of a international purpose and memory API, and help for the open source Linux/RISC-V instruction set architecture (ISA).

With this latest milestone in the release process for common Java, other prepared capabilities these types of as common generics and benefit objects will have to wait for a later version of the system. JDK 19 follows the March 22 arrival of JDK 18. Typical Java is on a six-thirty day period release cadence.

JDK 19 is slated to be formally launched for output use on September 20, preceded by a next rampdown phase commencing July 21, and release candidates to be released August 11 and August 25. Early accessibility builds of JDK 19 can be accessed from jdk.java.internet/19. The JDK 19 functions include:

  • Structured concurrency, in an incubator phase, is supposed to simplify multithreaded programming by a structured concurrency library. This concurrency treats multiple jobs managing in different threads as a single unit of function, to streamline mistake dealing with and cancellation. Trustworthiness and observability are enhanced.
  • A preview of report designs, to deconstruct history values. History designs and variety designs can be nested to help a declarative, strong, and composable variety of knowledge navigation and processing. Goals of the proposal consist of extending sample matching to convey far more complex, composable data queries while not altering the syntax or semantics of sort patterns. This proposal builds on pattern matching for instanceof, delivered in JDK 16  in March 2021. Potential plans could get in touch with for file designs to be extended with abilities these kinds of as array styles and vararg patterns. History styles is element of Project Amber, an work to take a look at and incubate smaller sized, productiveness-oriented Java attributes.
  • A preview of a overseas function and memory API, which would introduce an API by which Java applications can interoperate with code and details outside the house the Java runtime. By successfully invoking overseas capabilities (i.e., code outside the house the Java runtime) and securely accessing international memory (i.e., memory not managed by the JVM) the API permits Java plans to call native libraries and method indigenous details without the danger and brittleness of the Java Native Interface (JNI). The international operate and memory API combines two earlier incubating APIs: the foreign memory access API and the international linker API. The overseas functionality and memory API was formerly incubated in JDK 17 and reincubated in JDK 18. The proposal’s objectives incorporate relieve of use, general performance, generality, and basic safety.
  • A preview of digital threads, which are light-weight threads that significantly cut down the hard work of producing, sustaining, and observing large-throughput, concurrent applications. Targets include things like enabling server purposes written in the basic thread-per-request style to scale with close to-ideal hardware utilization, enabling existing code that employs the java.lang Thread API to undertake digital threads with minimum improve, and empower troubleshooting, debugging, and profiling of virtual threads with existing JDK equipment. It is not a target of this proposal to modify the primary concurrency design in Java or offer you a new information parallelism assemble in possibly the Java language or Java libraries. Nor is it a target to clear away the classic implementation of threads or to silently migrate existing programs to use virtual threads.
  • A third preview of pattern matching for change expressions and statements, extending pattern matching to swap, to allow an expression to be examined from a range of styles, each individual with a precise motion, so complex details-oriented queries can be expressed concisely and safely. This ability previously was previewed in JDK 17 and JDK 18. The third preview would insert refinements including the substitute of guarded styles with when clauses in change blocks. Also, the runtime semantics of a sample switch when the benefit of the selector expression is null are far more intently aligned with legacy swap semantics. The plan’s plans include expanding the expressiveness and applicability of swap expressions and statements by making it possible for styles to surface in scenario labels. Other plans involve allowing developers to unwind the historic null-hostility of switch when preferred, growing the protection of switch statements and ensuring that existing change expressions and statements keep on to compile with no changes and execute with similar semantics.
  • A fourth incubation of a vector API that would express vector computations that reliably compile at runtime to optimum vector instructions on supported CPU architectures, so attaining effectiveness outstanding to equal scalar computations. Developers employing the API attain a way to produce complex vector algorithms in Java, making use of the HotSpot auto-vectorizer but with a user product that will make vectorizations a lot more predictable and robust. The vector API previously was incubated into JDK 16, JDK 17, and JDK 19.
    Enhancements to the API proposed for JDK 19 contain enhancements to load and keep vectors to and from MemorySegments, as defined by the International Purpose and Memory API preview. JDK 19 would also increase two cross-lane vector operations, compress and grow, alongside one another with a complementary vector mask compress procedure. The compress vector procedure maps lanes of a resource vector, selected by a mask, to a destination vector in lane buy, although the expand operation does the inverse. The compress procedure is valuable in filtering query final results.
    In another addition to the vector API, bitwise integral lanewise functions would be expanded, such as functions this sort of counting the amount of 1 bits, reversing the buy of bits, and compressing and increasing bits. Objectives of the API integrated currently being clear and concise, platform-agnostic, possessing responsible runtime and compilation overall performance on x64 and AArch64 architectures, and enabling “graceful” degradation, for scenarios in which a vector computation can not be thoroughly expressed at runtime as a sequence of vector functions.
  • With the Linux/RISC-V port, Java would achieve aid for a hardware instruction established that is by now supported by a broad vary of language toolchains. RISC-V actually is a spouse and children of associated ISAs. The Linux/RISC-V port would only guidance the RV64GV configuration of RISC-V, a common reason 64-little bit ISA that includes vector recommendations. The builders of Java may possibly look at other RISC-V configurations in the potential.

The port would help the adhering to HotSpot VM possibilities: the template interpreter, C1 (consumer) JIT compiler, C2 (server) JIT compiler, and all present mainline garbage collectors together with ZGC and Shenandoah. The precise porting is just about complete the emphasis of the JDK Enhancement Proposal (JEP) is integration of the port into the JDK mainline repository.

Like JDK 18, JDK 19 is because of to be a short-phrase release, with only 6 months of top rated-stage, Premier aid.

The previous release, JDK 17, was a Long Expression Assistance (LTS) release, with numerous several years of help. It arrived September 14, 2021.

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