Java 22 Packs a Punch with 12 JEPs and Support for GenAI

Last month, Oracle dropped Java 22, adding a fresh batch of performance, stability, and security features to the venerable programming platform. This latest iteration introduces 12 JDK Enhancement Proposals (JEPs) aimed at refining everything from the Java language to its array of development tools. Though not a long-term support (LTS) release (the next LTS is Java 23), this release is a significant upgrade that includes new features focused on better enabling the use of Java for building AI applications.

Under the hood, Oracle is delivering language improvements from OpenJDK Project Amber, enhancements from Project Panama, features related to Project Loom, core libraries and tools capabilities, and performance updates.

"The new enhancements in Java 22 enable more developers to quickly and easily build and deliver feature-rich, scalable, and secure applications to help organizations across the globe grow their businesses," said Georges Saab, senior vice president in Oracle's Java Platform group and chair of the OpenJDK governing board, in a statement. "By delivering enhancements that streamline application development and extend Java's reach to make it accessible to developers of all proficiency levels, Java 22 will help drive the creation of a wide range of new applications and services for organizations and developers alike."

Among the stand-out features in this release, noted Sharat Chander, senior director of product management for the Java Platform at Oracle, is JEP 463, " Implicitly Declared Classes and Instance Main Methods," which is going to provide a kind of on-ramp for the next generation of developers to become familiar with Java, and eventually, active users.

"I'm very excited about  JEP 463," Chander told me. "It sort of welcomes a whole new generation of developers that might think Java is outdated. Of course, it's far from [that], based on all the innovation that have been coming since we started this six-month release cadence."

"The original founders of this entire concept and technology realized that you have to build a user base and a community to have something that's active," he added, "and you see a lot of modern languages, platforms, and solutions that have now realized that the secret sauce is to emulate what Java has done. For us, this is paramount to [Java's] success."

Arnal Dayaratna, research vice president in IDC's software development group, underscored Java's "versatility and comprehensive toolset," which enables it to support the development of production-grade, mission-critical applications at scale. This "positions it as a key enabling technology for innovative use cases such as generative AI."

"After nearly three decades, Java's ability to support complex development tasks that span a wide range of use cases makes the platform as relevant as it has ever been," Dayaratna said in a statement. "

Java 22 includes a number of features in preview, which Saab told me reflects the benefits of the six-month release cadence Oracle continues to maintain.

"In the old days, it was always a problem getting feedback on features," he said. "We would work on something and have early access builds, which a few passionate people would download and try. But people have day jobs! Most just weren't going to download something, try it, and give feedback. And if they did, it was probably too late to do anything about it. Now, the whole intent of the preview feature is put it in something that people are downloading anyway and make it super easy to try it and give us feedback on it."

The list of updates delivered in Java 22 includes:

• JEP 447: Statements before super(…) (Preview): Gives developers the freedom to express the behavior of constructors. By allowing statements that do not reference the instance being created to appear before an explicit constructor invocation, this feature enables a more natural placement of logic that needs to be factored into auxiliary static methods, auxiliary intermediate constructors, or constructor arguments. It also preserves the existing assurance that constructors run in top-down order during class instantiation, helping ensure that code in a subclass constructor cannot interfere with superclass instantiation. In addition, this feature does not require any changes to the Java Virtual Machine (JVM) and relies only on the current ability of the JVM to verify and execute code that appears before explicit constructor invocations within constructors.

• JEP 456: Unnamed Variables & Patterns: Helps improve developer productivity by enhancing the Java language with unnamed variables and patterns, which can be used when variable declarations or nested patterns are required but never used. This reduces opportunities for error, improves the readability of record patterns, and increases the maintainability of all code.

• JEP 459: String Templates (Second Preview): Simplifies the development of Java programs by making it easy to express strings that include values computed at run time, while also improving the security of programs that compose strings from user-provided values and pass them to other systems. Additionally, the readability of expressions mixed with text is enhanced, and non-string values computed from literal text and embedded expressions can be created without having to transit through an intermediate string representation.

• JEP 463: Implicitly Declared Classes and Instance Main Methods (Second Preview): Helps accelerate learning by offering a smooth on-ramp to Java programming to enable students to write their first programs without needing to understand language features designed for large programs. With this feature, educators can introduce concepts in a gradual manner and students can write streamlined declarations for single-class programs and seamlessly expand their programs to use more advanced features as their skills grow.

Project Loom Features

• JEP 462: Structured Concurrency (Second Preview): Helps developers streamline error handling and cancellation and enhance observability by introducing an API for structured concurrency. This helps promote a style of concurrent programming that can eliminate common risks arising from cancellation and shutdown – such as thread leaks and cancellation delays – and improves the observability of concurrent code.

• JEP 464: Scoped Values (Second Preview): Helps increase ease-of-use, comprehensibility, performance, and robustness of developers' projects by enabling the sharing of immutable data within and across threads.

Project Panama Features

• JEP 454: Foreign Function & Memory API: Increases ease-of-use, flexibility, safety, and performance for developers by introducing an API to enable Java programs to interoperate with code and data outside of the Java runtime. By efficiently invoking foreign functions such as code outside the Java Virtual Machine, and by safely accessing foreign memory (i.e., memory not managed by the JVM), the new API allows Java programs to call native libraries and process native data without requiring the Java Native Interface.

• JEP 460: Vector API (Seventh Incubator): Enables developers to achieve performance superior to equivalent scalar computations by introducing an API to express vector computations that reliably compile at runtime to vector instructions on supported CPU architectures.  

Core Libraries & Tools Features

• JEP 457: Class-File API (Preview): Helps developers improve productivity by providing a standard API for parsing, generating, and transforming Java class files.

• JEP 458: Launch Multi-File Source-Code Programs: Enables developers to choose whether and when to configure a build tool by enhancing the Java application launcher to enable it to run a program supplied as multiple files of Java source code.

• JEP 461: Stream Gatherers (Preview): Helps developers improve productivity by enhancing the Stream API to support custom intermediate operations, which will allow stream pipelines to transform data in ways that are not easily achievable with the existing built-in intermediate operations. By making stream pipelines more flexible and expressive and allowing custom intermediate operations to manipulate streams of infinite size, this feature enables developers to become more efficient in reading, writing, and maintaining Java code.

Performance Updates

• JEP 423: Region Pinning for G1: Helps reduce latency by allowing some garbage collection to happen during some native library calls that would have otherwise needed to pause the collector. This is achieved by tracking which objects need to be blocked during these native library calls and "pinning" just the regions that contain these objects. This allows garbage collection to continue normally in unpinned regions, even during what would have otherwise been a blocking native library call.

Posted by John K. Waters on April 10, 2024