2022 and 2023 Java Platform news and new features, code examples - English

The Java platform has seen significant updates and new features in 2022 and 2023, with the release of Java 20 and Java 21.

Java 20, released in March 2023, introduced several enhancements. Key features include:

Record Patterns and Pattern Matching for Switch: These features from OpenJDK project Amber enhance data navigation and processing, making data-oriented queries more sophisticated and composable.

Project Loom: This includes Scoped Values, Virtual Threads, and Structured Concurrency, aimed at streamlining the process of writing, maintaining, and observing high-throughput, concurrent applications.

Project Panama: The release brings enhancements like the Foreign Function & Memory API and Vector API, improving the interconnectivity between Java Virtual Machine (JVM) and native code.

Java 21, scheduled for release in September 2023, will be a Long-Term Support (LTS) version, bringing further advancements:

String Templates: This feature will simplify the development of Java programs by making it easier to express strings that include values computed at runtime.

Record Patterns (Third Preview) and Pattern Matching for Switch: These features will continue to evolve, enhancing the expressiveness of the Java language.

Unnamed Patterns and Variables, and Unnamed Classes and Instance Main Methods (Preview): These are aimed at simplifying Java language and improving accessibility, particularly for educational purposes.

Project Panama Enhancements: These include the third preview of the Foreign Function & Memory API and the sixth incubator of the Vector API.

In addition to these language updates, the Java ecosystem has seen trends such as increasing importance of cloud computing, AI, machine learning, and the evolution of the Spring Framework. Spring Framework 6 and Hibernate 6, both of which were released in late 2022, offer compatibility with JDK 17 and bring performance improvements.

The future of Java in areas like cloud-native technology, AI, and mobile development, particularly Android, remains bright. The demand for Java developers continues to be strong, with significant job opportunities and competitive salaries.

The Java community is also benefiting from improved learning resources, making Java easier to learn than ever. Tools like JShell, cloud-based IDEs, and the resurgence of Java User Groups (JUGs) and JavaOne conference are contributing to a more vibrant Java ecosystem.

For more detailed information, you can refer to the sources from Oracle's website regarding Java 20 and Java 21, as well as insights from CodeGym, Red Hat Developer, and TheServerSide.

Explain and give code examples

Certainly! Let's dive into some of the key features of Java 20 and Java 21 with explanations and code examples.

Java 20 Features

Record Patterns (JEP 432)

Record Patterns allow for more sophisticated data queries by nesting record patterns and type patterns.

Example:

java

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record Point(int x, int y) {}

var point = new Point(1, 2);

if (point instanceof Point(int x, int y)) {

    System.out.println("X: " + x + ", Y: " + y);

}

Pattern Matching for Switch (JEP 433)

This feature extends pattern matching to switch expressions, enabling concise and safe expression of complex data-oriented queries.

Example:

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Object obj = "Hello";

String result = switch (obj) {

    case String s -> "String: " + s;

    case Integer i -> "Integer: " + i;

    default -> "Unknown type";

};

System.out.println(result);

Virtual Threads (JEP 436)

Virtual threads significantly streamline writing, maintaining, and observing high-throughput, concurrent applications.

Example:

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try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {

    executor.submit(() -> System.out.println("Running in a virtual thread"));

}

Structured Concurrency (JEP 437)

It simplifies multithreaded programming by treating multiple tasks as a single unit of work.

Example:

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try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {

    Future<?> task1 = scope.fork(() -> doTask1());

    Future<?> task2 = scope.fork(() -> doTask2());

    scope.join();

}

Java 21 Features

String Templates (JEP 430)

Simplifies the development of Java programs by improving the expressiveness and readability of string creation.

Example:

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String name = "Java";

String message = `Hello, ${name}!`; // This is a hypothetical syntax, as Java 21 is not yet released.

Record Patterns (Third Preview) (JEP 440)

Continues to enhance pattern matching for record classes.

Example: Similar to the Java 20 example, but with more complex nested patterns.

Unnamed Patterns and Variables (JEP 443)

Enhances the Java language by allowing unnamed patterns in record components.

Example:

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record User(String name, int age) {}

User user = new User("Alice", 30);

if (user instanceof User(String, int a) && a >= 18) {

    System.out.println("Adult user");

}

Foreign Function & Memory API (Third Preview) (JEP 442)

Improves the ability of Java programs to interoperate with foreign code and data.

Example: This would involve using the API to call native libraries or access foreign memory.

These examples demonstrate the syntax and basic usage of some of the new features in Java 20 and the upcoming Java 21. Remember, some features are in preview, meaning they might not be fully stable and could change before the final release. Always refer to the official Java documentation for the most accurate and detailed information.