JDK 19: The features targeted for Java 19

Java Advancement Package 19, because of this September, has just experienced a sixth feature proposed for it: a preview of document patterns, for knowledge navigation and processing. Record designs joins five earlier attributes, ranging from a preview of a overseas operate and memory API to guidance for the open source Linux/RISC-V instruction set architecture (ISA).

JDK 19, or basically Java 19, most likely could host a vast amount of capabilities, ranging from universal generics to price objects, according to plans underway for improving Java. JDK 19 would stick to JDK 18, which arrived March 22. Standard Java is on a 6-month launch cadence.

OpenJDK’s builders have published an official release timetable for JDK 19, which has it arriving September 20 as a generation release, preceded by rampdown phases June 9 and July 21, and launch candidates to be printed August 11 and August 25.

Early obtain builds of JDK 19 can be accessed from jdk.java.web/19. Proposed JDK 19 attributes include things like:

• A preview of report patterns, to deconstruct history values. Record patterns and sort styles can be nested to allow a declarative, highly effective, and composable form of knowledge navigation and processing. Objectives of the proposal contain extending sample matching to express additional complex, composable details queries whilst not changing the syntax or semantics of style designs. This proposal builds on sample matching for instanceof, delivered in JDK 16  in March 2021. Long term strategies may possibly get in touch with for history styles to be extended with abilities these kinds of as array styles and vararg patterns. History styles is element of Task Amber, an effort and hard work to explore and incubate scaled-down, productivity-oriented Java characteristics.
• A preview of a international purpose and memory API, which would introduce an API by which Java plans can interoperate with code and knowledge outside the Java runtime. By effectively invoking international capabilities (i.e., code outside the house the Java runtime) and safely and securely accessing international memory (i.e., memory not managed by the JVM) the API permits Java systems to connect with native libraries and procedure indigenous info with no the danger and brittleness of the Java Native Interface (JNI). The overseas function and memory API brings together two before incubating APIs: the international memory obtain API and the overseas linker API. The overseas operate and memory API was formerly incubated in JDK 17 and reincubated in JDK 18. The proposal’s goals incorporate relieve of use, effectiveness, generality, and safety.
• A preview of digital threads, which are lightweight threads that significantly cut down the effort and hard work of crafting, maintaining, and observing higher-throughput, concurrent apps. Plans include enabling server applications composed in the easy thread-per-request fashion to scale with around-ideal components utilization, enabling existing code that uses the java.lang Thread API to adopt digital threads with nominal alter, and empower troubleshooting, debugging, and profiling of virtual threads with current JDK equipment. It is not a target of this proposal to alter the fundamental concurrency model in Java or provide a new details parallelism assemble in possibly the Java language or Java libraries. Nor is it a purpose to take away the conventional implementation of threads or to silently migrate current apps to use digital threads.
• A 3rd preview of sample matching for swap expressions and statements, extending sample matching to swap, to allow an expression to be examined from a amount of styles, each with a unique action, so sophisticated details-oriented queries can be expressed concisely and safely and securely. This capability beforehand was previewed in JDK 17 and JDK 18. The third preview would insert refinements including the replacement of guarded designs with when clauses in switch blocks. Also, the runtime semantics of a pattern switch when the price of the selector expression is null are much more intently aligned with legacy swap semantics. The plan’s ambitions consist of growing the expressiveness and applicability of change expressions and statements by making it possible for designs to surface in scenario labels. This will permit builders to take it easy the historic null-hostility of switch when wanted, and is meant to boost the safety of change statements and ensure that current change expressions and statements continue on to compile with no improvements and execute with identical semantics.
• A fourth incubation of a vector API that would categorical vector computations that reliably compile at runtime to optimal vector directions on supported CPU architectures, so reaching effectiveness excellent to equal scalar computations. Developers working with the API achieve a way to publish complex vector algorithms in Java, working with the HotSpot car-vectorizer but with a person design that will make vectorizations a lot more predictable and robust. The vector API formerly was incubated into JDK 16, JDK 17, and JDK 19.
  Enhancements to the API proposed for JDK 19 consist of enhancements to load and retailer vectors to and from MemorySegments, as defined by the Overseas Operate and Memory API preview. JDK 19 would also increase two cross-lane vector operations, compress and broaden, collectively with a complementary vector mask compress operation. The compress vector operation maps lanes of a supply vector, selected by a mask, to a vacation spot vector in lane buy, whilst the increase procedure does the inverse. The compress procedure is beneficial in filtering query final results.
  In one more addition to the vector API, bitwise integral lanewide operations would be expanded, like functions these types of counting the quantity of just one bits, reversing the get of bits, and compressing and expanding bits. Targets of the API involved being apparent and concise, system-agnostic, owning trustworthy runtime and compilation performance on x64 and AArch64 architectures, and enabling “graceful” degradation, for conditions in which a vector computation are not able to be totally expressed at runtime as a sequence of vector functions.
• With the Linux/RISC-V port, Java would gain guidance for a hardware instruction established that is now supported by a large array of language toolchains. RISC-V actually is a relatives of related ISAs. The Linux/RISC-V port would only guidance the RV64GV configuration of RISC-V, a typical purpose 64-little bit ISA that consists of vector instructions. The builders of Java may perhaps look at other RISC-V configurations in the foreseeable future.

The port would aid the adhering to HotSpot VM solutions: the template interpreter, C1 (shopper) JIT compiler, C2 (server) JIT compiler, and all latest mainline garbage collectors like ZGC and Shenandoah. The true porting is nearly complete the focus of the JDK Enhancement Proposal (JEP) is integration of the port into the JDK mainline repository.

Like JDK 18, JDK 19 is due to be a quick-term launch, with only 6 months of major-level, Premier assist.

The previous launch, JDK 17, was a Long Phrase Assistance (LTS) release, with a number of several years of assistance. It arrived September 14, 2021.