New Features in Java 25

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Hi everyone, welcome back.

Java 25 is almost here, and it’s a long-term-support release scheduled for September 2025. LTS releases are important because they’re the versions companies rely on for years in production. This means every improvement in Java 25 could influence millions of applications worldwide.

In this article, we’ll explore what’s new in Java 25, why these changes matter, and we’ll look at simple code examples so even if you’re new to Java, you’ll understand.

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Overview

Java 25 builds on the modernization efforts we saw in Java 21 and 22. It makes the language syntax cleaner, improves compiler behavior, and introduces new APIs for concurrency, security, and performance. The goal is to make Java more expressive for developers while keeping the platform robust for enterprise workloads.

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Language and Compiler Features

1. Primitive Types in Patterns — JEP 507

Pattern matching in Java is getting more powerful. In earlier versions, pattern matching mostly worked with objects. Now, primitive types like int or double can be matched directly.

Example:

static void test(Object obj) {
    if (obj instanceof int i) {
        System.out.println("It's an int: " + i);
    }
}

Why does this matter? Before, handling primitives required extra casting or verbose code. Now you can write cleaner, shorter checks—perfect for switch statements or validation logic. This is part of Java’s broader mission to unify type patterns across the language.

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2. Module Import Declarations — JEP 511

Modules were introduced in Java 9, but they weren’t always easy to read or maintain. In Java 25, you can now declare module dependencies directly at the top of a Java file using:

import module java.base;

This is similar to normal imports but clarifies which module provides which classes. It also helps tools infer dependencies automatically, which makes working on modular projects less confusing.

But there’s a catch: sometimes modules export classes with the same name. For example, both java.util and java.sql have a Date class:

import module java.base;
import module java.sql;

public class Main {
    public static void main(String[] args) {
        Date d = Date.valueOf("2025-06-15"); // Ambiguous
    }
}

This will cause a compile error saying “reference to Date is ambiguous.” To fix it, you import the specific class you need:

import java.sql.Date;

This feature makes modular code easier to read, but you still need to be precise when names collide.

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3. Compact Source Files and Instance Main Methods — JEP 512

One of the coolest beginner-friendly updates is compact source files. You can now write a Java program without a class declaration:

void main() {
    System.out.println("Hello from Java 25!");
}

This is huge for teaching, quick demos, or scripting. No more boilerplate public class Main { … } for simple tasks. It lowers the barrier for new developers and makes Java feel lighter for small experiments.

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4. Flexible Constructor Bodies — JEP 513 (Final)

Before Java 25, constructors had a strict rule: you had to call super() or this() as the very first line. This often meant duplicating validation logic or creating static helpers.

Now, you can place validation code before the super() call.

Example:

class Employee extends Person {
    final String name;

    Employee(String name, int age) {
        if (age < 18 || age > 67)
            throw new IllegalArgumentException("Age must be between 18 and 67");
        super(age); // Can now appear after validation
        this.name = name;
    }
}

This makes constructors cleaner and improves fail-fast behavior, catching invalid data early without breaking Java’s safety rules.

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Scoped Values — JEP 506 (Final)

Imagine you need to pass user information or request context down through different layers of your app—like service calls or asynchronous tasks. Traditionally, developers used ThreadLocal, but it could leak memory or behave unpredictably with virtual threads.

Scoped Values solve this problem. They’re lightweight, immutable, and thread-safe, designed to work perfectly with modern concurrency.

Example:

static final ScopedValue<String> USER = ScopedValue.newInstance();

ScopedValue.where(USER, "Alice").run(() -> {
    System.out.println("User: " + USER.get());
});

Scoped Values make it safer and faster to pass context without risking leaks or synchronization overhead.

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Structured Concurrency — JEP 505 (Fifth Preview)

Multi-threaded programming is hard. You spin up several tasks—fetching user data, loading an order, checking inventory—but managing their lifecycles can get messy.

Structured Concurrency treats related threads as a single unit. You open a scope, fork tasks inside it, wait for them, and handle errors consistently:

try (var scope = StructuredTaskScope.<String>open()) {
    var userTask = scope.fork(() -> fetchUser());
    var orderTask = scope.fork(() -> fetchOrder());
    scope.join();
    System.out.println(userTask.get() + " - " + orderTask.get());
}

When the scope closes, Java makes sure every task finishes or is cancelled. This approach **improves reliability** and **keeps code readable**, especially with virtual threads.

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Stable Value API — JEP 502 (Preview)

Stable Values are like a safer, context-aware version of Optional. They let you share immutable values across threads or computations without worrying about unexpected changes.

Example:

var greeting = StableValue.<String>of();
String message = greeting.orElseSet(() -> "Hello from StableValue!");
System.out.println(message);

This is useful for caching results, lazy evaluation, or ensuring that multiple threads always read the **same consistent value**.

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PEM Encodings of Cryptographic Objects — JEP 470 (Preview)

Handling PEM-encoded keys and certificates—like those used with OpenSSL—often required third-party libraries.

In Java 25, you can now read and write PEM files natively using the standard security APIs. That means loading RSA keys or X.509 certificates directly without extra tools, improving security and interoperability with existing systems.

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Vector API — JEP 508 (Tenth Incubator)

The Vector API lets Java express data-parallel computations that compile into SIMD instructions on modern CPUs. For workloads like machine learning, image processing, or scientific calculations, this can bring near-native performance right in Java. Just remember to enable preview and incubator modules when using it.

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Key Derivation Function API — JEP 510 (Final)

Security is stronger in Java 25 thanks to a standard Key Derivation Function API. You can now implement algorithms like PBKDF2 or scrypt—used to derive encryption keys from passwords—without external libraries. This reduces vulnerabilities and ensures consistent, supported cryptographic practices.

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Other Runtime and Tooling Improvements

Java 25 includes many behind-the-scenes upgrades that boost performance and observability:

• JEP 503: Removes legacy 32-bit x86 support to focus on modern architectures.
• JFR CPU-Time Profiling (JEP 509): Lets Java Flight Recorder track exact CPU usage per method or thread.
• Ahead-of-Time Ergonomics (JEP 514) and Method Profiling (JEP 515): Lay groundwork for future AOT compilation by identifying performance bottlenecks.
• JFR Cooperative Sampling (JEP 518): Reduces profiling overhead by aligning sampling with safe points suggested by your app.
• Compact Object Headers (JEP 519): Shrinks Java object headers on 64-bit systems, cutting memory use—great for microservices and large heaps.
• JFR Method Timing and Tracing (JEP 520): Captures precise timing data for all method calls, offering better insights into execution flow.
• Generational Shenandoah (JEP 521): Adds generational garbage collection to Shenandoah, improving throughput and pause times for enterprise apps.

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What Developers Need to Know

Many of these features are still preview or incubator. To compile and run them, use flags like:

javac --enable-preview --release 25 --add-modules jdk.incubator.vector MyClass.java  
java --enable-preview --add-modules jdk.incubator.vector MyApp

Always check the **JDK release notes**—APIs may change before finalization. Avoid using preview features in production unless you’re ready to update them later.

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Wrap-Up

Java 25 isn’t just another update—it’s a major LTS release that modernizes everything from syntax and concurrency to security and performance tools. It shows Java’s commitment to cutting-edge hardware, developer productivity, and secure, efficient applications. Upgrading means you’ll benefit from improvements made since Java 21, and you’ll be ready for the future of Java development.