Java Features in 2025

Introduction:

As we step into 2025, Java continues to evolve, pushing boundaries, enhancing performance, and simplifying development processes. Here’s a detailed look at some of the pivotal features and trends shaping Java this year.

Java Features in 2025:

1. Virtual Threads:

Java’s introduction of virtual threads has been one of the most significant advancements in managing concurrency. With Project Loom, Java developers can now handle thousands or even millions of lightweight virtual threads, which do not map directly to OS threads. This feature makes concurrent programming much more accessible and efficient, reducing the complexity associated with traditional threading models.

• Impact: Dramatically improves scalability and simplifies the development of high-performance applications.
• Use Case: Ideal for web servers, real-time systems, or any application dealing with high concurrency.

Example: Virtual threads allow for more efficient handling of concurrent operations.

import jdk.incubator.concurrent.StructuredTaskScope;

public class VirtualThreadExample {
    public static void main(String[] args) throws Exception {
        try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
            scope.fork(() -> {
                System.out.println("Task 1 running on: " + Thread.currentThread());
                return "Task 1 Result";
            });
            scope.fork(() -> {
                System.out.println("Task 2 running on: " + Thread.currentThread());
                return "Task 2 Result";
            });

            scope.join();
            scope.throwIfFailed();
        }
    }
}

2. Structured Concurrency:

This feature enhances Java’s ability to manage concurrent tasks by introducing a structured approach to concurrency. It helps in coordinating multiple threads in a more organized way, reducing the risk of resource leaks and simplifying error handling.

• Impact: Offers a clearer, more maintainable way to write concurrent code.
• Use Case: Beneficial for applications where complex operations need to be broken down into smaller, manageable tasks.

Example: Manage multiple threads in a structured way, ensuring all initiated tasks are completed or canceled before the scope is closed.

import jdk.incubator.concurrent.StructuredTaskScope;

public class StructuredConcurrencyExample {
    public static void main(String[] args) throws Exception {
        try (var scope = new StructuredTaskScope<>()) {
            Task<String> task1 = scope.fork(() -> {
                Thread.sleep(1000);
                return "Task 1 completed";
            });
            Task<String> task2 = scope.fork(() -> {
                Thread.sleep(2000);
                return "Task 2 completed";
            });

            scope.joinUntil(() -> task1.state() != Task.State.RUNNING && task2.state() != Task.State.RUNNING);
            System.out.println(task1.get());
            System.out.println(task2.get());
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
}

3. Scoped Values:

Scoped values, introduced as an incubator API in JDK 20, provide a mechanism to share immutable data across threads without the complexities of thread-local variables. This feature is particularly useful when working with large numbers of virtual threads, ensuring data integrity and ease of debugging.

• Impact: Enhances the safety and efficiency of data sharing in multithreaded environments.
• Use Case: Useful in scenarios where you need to pass data to child threads or across different parts of an application.

Example: Share immutable data across threads within a scope.

import jdk.incubator.concurrent.ScopedValue;

public class ScopedValueExample {
    static final ScopedValue<String> USERNAME = ScopedValue.newInstance();

    public static void main(String[] args) {
        ScopedValue.where(USERNAME, "Alice", () -> {
            System.out.println(USERNAME.get()); // Prints: Alice
        });
    }
}

4. Generational Shenandoah Garbage Collector:

The Shenandoah garbage collector, now with generational capabilities, promises to reduce pause times significantly in Java applications. This is vital for applications requiring low-latency operations.

• Impact: Improves the performance of applications by reducing garbage collection pauses.
• Use Case: Particularly relevant for real-time systems, gaming, and applications where responsiveness is critical.

Example: No specific code example as this is more of a JVM configuration setting, but here’s how you might enable it:

java -XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC -XX:ShenandoahGCMode=generational YourApp

5. Vector API Enhancements:

The Vector API, now refined through multiple incubations, provides developers with the tools to leverage SIMD (Single Instruction, Multiple Data) capabilities of modern CPUs for performance optimization in numeric computations.

• Impact: Boosts performance of data-parallel operations, making Java competitive in fields like scientific computing or machine learning.
• Use Case: Ideal for any application performing extensive numerical calculations or data processing.

Example: Performance optimizations for data-parallel operations.

import jdk.incubator.vector.FloatVector;
import jdk.incubator.vector.VectorSpecies;

public class VectorAPIExample {
    private static final VectorSpecies<Float> SPECIES = FloatVector.SPECIES_256;

    public static void main(String[] args) {
        float[] a = {1.0f, 2.0f, 3.0f, 4.0f};
        float[] b = {5.0f, 6.0f, 7.0f, 8.0f};
        float[] result = new float[a.length];

        for (int i = 0; i < a.length; i += SPECIES.length()) {
            var m = FloatVector.fromArray(SPECIES, a, i);
            var n = FloatVector.fromArray(SPECIES, b, i);
            var r = m.add(n);
            r.intoArray(result, i);
        }
        System.out.println(Arrays.toString(result)); // [6.0, 8.0, 10.0, 12.0]
    }
}

6. Key Derivation Function API:

With the rise of quantum computing threats, Java 24 introduces a new API for Key Derivation Functions (KDFs), enhancing the security of cryptographic operations.

• Impact: Prepares Java applications for future security challenges by strengthening key management practices.
• Use Case: Essential for applications dealing with secure data transmission, encryption, and authentication.

Example: Enhanced security for cryptographic key management.

import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;

public class KDFExample {
    public static void main(String[] args) throws Exception {
        String password = "mypassword";
        byte[] salt = new byte[16]; // should be randomly generated
        int iterationCount = 65536;
        int keyLength = 256;

        SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
        PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt, iterationCount, keyLength);
        byte[] key = skf.generateSecret(spec).getEncoded();

        System.out.println("Key: " + java.util.Base64.getEncoder().encodeToString(key));
    }
}

7. Stream Gatherers:

Introduced as a preview feature, stream gatherers allow for more flexible and powerful stream operations, particularly for custom aggregation or sorting tasks.

• Impact: Extends the capabilities of Java Streams, making complex data operations more intuitive.
• Use Case: Useful in data analysis, business intelligence, or any scenario where custom data processing is needed.

Example: Custom operations on streams.

import java.util.stream.Stream;

public class StreamGathererExample {
    public static void main(String[] args) {
        Stream.of(1, 2, 3, 4, 5, 6)
              .collect(new CustomCollector())
              .forEach(System.out::println); // Example output depends on CustomCollector implementation
    }
}

8. Compact Object Headers:

Aimed at reducing memory overhead, this experimental feature in Java 24 reduces the size of object headers, leading to better memory utilization.

• Impact: Enhances deployment density and data locality, which can lead to performance improvements in memory-constrained environments.
• Use Case: Beneficial for environments with limited resources or high-density deployments like microservices.

Example: This is more of a JVM configuration, not directly illustrated with code, but here’s how you might enable it:

java -XX:+UseCompactObjectHeaders YourApp

Conclusion:

Java in 2025 is not just about maintaining its place in the programming ecosystem but actively expanding its capabilities. These features underscore Java’s commitment to performance, security, and developer productivity, ensuring it remains a top choice for enterprise and modern application development. Whether you’re a seasoned Java developer or new to the language, these advancements offer exciting opportunities to explore and implement.

Stay tuned to these developments, and continue to leverage Java’s robust ecosystem to build scalable, efficient, and secure applications.