What’s New in Java 23: A Practical Guide for Developers

Java 23, the latest release in the Java ecosystem, brings a host of exciting new features, performance improvements, and enhancements that modern developers will appreciate. This article explores the most significant updates in Java 23 and how they impact your development workflow.

1. Enhanced Pattern Matching

Java 23 continues to improve pattern matching with more expressive and powerful capabilities, making code more concise and readable.

Example:

sealed interface Shape permits Circle, Rectangle {}
final class Circle implements Shape { double radius; }
final class Rectangle implements Shape { double width, height; }

static double getArea(Shape shape) {
    return switch (shape) {
        case Circle c -> Math.PI * c.radius * c.radius;
        case Rectangle r -> r.width * r.height;
    };
}

2. Improved String Handling

  • transform() Enhancements - Allows more flexible transformation of string data.

  • New Unicode Support - Better handling of multilingual text and symbols.

  • Performance Optimizations - Faster string operations, reducing execution time in large-scale applications.

Example:

String result = "hello".transform(str -> str.toUpperCase() + " WORLD!");
System.out.println(result); // Output: HELLO WORLD!

4. Advanced HTTP Client API Features

The HttpClient API has been refined with:

  • Improved WebSocket support.

  • Built-in caching mechanisms.

  • Faster response handling for high-performance applications.

Example:

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create("https://api.example.com"))
        .GET()
        .build();
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
System.out.println(response.body());

5. More Efficient Garbage Collection

Java 23 introduces further optimizations in garbage collection, improving memory management and reducing latency for large-scale applications.

6. Modernized Security Features

  • Stronger TLS 1.3 Enhancements for improved encrypted communication.

  • More Robust Cryptographic Algorithms integrated into the Java platform.

Example:

SecureRandom secureRandom = SecureRandom.getInstanceStrong();
byte[] randomBytes = new byte[16];
secureRandom.nextBytes(randomBytes);
System.out.println(Arrays.toString(randomBytes));

7. Java Virtual Threads

Java 23 refines Project Loom’s virtual threads, making concurrent programming even more scalable and efficient with minimal thread overhead.

Example:

try (var executor = Executors.newVirtualThreadPerTaskExecutor()) {
    executor.submit(() -> System.out.println("Hello from virtual thread!"));
}

8. Removal of Legacy APIs

To keep Java streamlined and efficient, outdated APIs and deprecated methods have been removed, ensuring a cleaner and more modern standard library. Some of the removed APIs include:

  • Deprecated Security Manager - Removed due to evolving security practices.

  • Final Removal of RMI Activation System - RMI activation has been obsolete for some time and is now fully removed.

  • Elimination of Old Socket API Implementations - Improved networking support by removing older, redundant socket APIs.

Example:

If your code relied on the Security Manager, an update may be needed:

// Old code (no longer valid in Java 23)
System.setSecurityManager(new SecurityManager());

// New approach
// Security policies should be enforced at the operating system or container level.

Similarly, if you previously used RMI Activation, consider migrating to alternative messaging frameworks like gRPC or modern REST APIs.

Example:

Migrating from RMI to gRPC:

// Old RMI code (removed in Java 23)
Registry registry = LocateRegistry.getRegistry("localhost", 1099);
MyRemoteInterface stub = (MyRemoteInterface) registry.lookup("MyService");
String response = stub.sayHello();

// New approach using gRPC
ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 50051).usePlaintext().build();
MyServiceGrpc.MyServiceBlockingStub stub = MyServiceGrpc.newBlockingStub(channel);
HelloResponse response = stub.sayHello(HelloRequest.newBuilder().setName("Java 23").build());
System.out.println(response.getMessage());
channel.shutdown();

Example:

Handling sockets with modern APIs:

// Old blocking socket API (removed in Java 23)
ServerSocket serverSocket = new ServerSocket(8080);
Socket clientSocket = serverSocket.accept();

// Modern non-blocking API
ServerSocketChannel serverChannel = ServerSocketChannel.open();
serverChannel.bind(new InetSocketAddress(8080));
serverChannel.configureBlocking(false);
SocketChannel clientChannel = serverChannel.accept();

Conclusion

Java 23 is a powerful release that enhances performance, security, and developer productivity. Its new features solidify Java’s position as a leading language for enterprise applications. With its improvements, Java 23 remains a robust choice for developers looking to build scalable, high-performance applications.

Are you using Java 23 in your projects? Share your experiences in the comments below!