Java 21’s Enhanced Features: Boosting Developer Productivity and App Performance

Java 21, released in September 2023, brings a range of improvements focusing on enhanced developer productivity and application performance. This post highlights some of the key features that make Java 21 a significant upgrade.

Enhanced Virtual Threads

Java 21 further refines its virtual threads (Project Loom), significantly improving concurrency handling. Virtual threads are lightweight, making it easier to manage thousands of concurrent tasks without the overhead of traditional threads.

Improved Performance and Scalability

Virtual threads reduce the resource consumption associated with managing many concurrent operations. This translates to better scalability and performance, especially in applications handling many simultaneous requests.

ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor();

for (int i = 0; i < 10000; i++) {
    executor.submit(() -> {
        // Perform some task
        System.out.println("Thread running: " + Thread.currentThread().getName());
    });
}

executor.shutdown();

Structured Concurrency

Structured concurrency, another feature introduced in previous releases and enhanced in Java 21, improves the management of multiple tasks running concurrently. It simplifies error handling and resource management.

Simplified Error Handling

With structured concurrency, exceptions thrown in any of the concurrently running tasks are properly handled without needing complex exception propagation mechanisms.

try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
    scope.fork(() -> { /* Task 1 */ });
    scope.fork(() -> { /* Task 2 */ });
    scope.join(); // Wait for all tasks to complete
} catch (Throwable e) {
    // Handle exceptions from any task
    System.err.println("Error: " + e.getMessage());
}

Improved Pattern Matching

Java 21 extends pattern matching for switch expressions and statements, allowing more concise and readable code.

Enhanced Switch Statements

The enhanced pattern matching allows you to switch on more complex data structures and perform pattern matching within the switch statement.

record Person(String name, int age) {}

Person person = new Person("John Doe", 30);

switch (person) {
    case Person p when p.age() > 25 -> System.out.println("Older person");
    case Person p -> System.out.println("Person's name: " + p.name());
    default -> System.out.println("Unknown");
}

Conclusion

Java 21 offers significant improvements in both developer productivity and application performance. The enhancements to virtual threads, structured concurrency, and pattern matching provide developers with powerful tools to build more efficient and robust applications. Adopting these features can significantly streamline development workflows and improve the overall quality of Java applications.