What’s New in Java 25? Explore the Game‑Changing Features and Performance Boosts

September 16, 2025 – Java 25 is officially released as the next LTS version, supported through 2030 and 2033. It marks a major milestone for the Java ecosystem.

Core Feature Overview

JEP 512 – Compact source files and instance main method

JEP 511 – Module import declarations

JEP 513 – Flexible constructor bodies

JEP 507 – Pattern matching for primitive types (preview)

JEP 505 – Structured concurrency (preview)

JEP 506 – Scoped values (stable)

JEP 519 – Compact object headers

JEP 514 & 515 – Simplified AOT compilation and startup analysis

JEP 521 – Generational Shenandoah GC

JEP 470 – PEM encoding API (preview)

JEP 508 – Vector API (incubator)

Core Language Features

1. Primitive‑type pattern matching (JEP 507)

Eliminate tedious boxing/unboxing by matching directly on primitive values:

Object thing = 42;
if (thing instanceof int i) {
    System.out.println("Primitive match: " + i);
}
int value = 42;
if (value instanceof byte b) {
    System.out.println("Byte: " + b);
} else if (value instanceof short s) {
    System.out.println("Short: " + s);
} else {
    System.out.println("Other: " + value);
}

2. Module import declaration (JEP 511)

Import an entire module with a single statement, replacing multiple traditional imports:

// Traditional imports
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

// Java 25 style
import module java.sql;

3. Compact source files and instance main method (JEP 512)

Write scripts without class declarations:

void main() {
    System.out.println("Yes, this is valid Java code!");
    System.out.println("Great for quick scripts and demos");
}

4. Flexible constructor rules (JEP 513)

Execute logic before the super() call:

public class User {
    private String name;
    public User(String name) {
        validate(name); // validation before super()
        super();
        this.name = name;
    }
    private void validate(String name) {
        if (name == null || name.trim().isEmpty()) {
            throw new IllegalArgumentException("Name cannot be empty");
        }
    }
}

Performance & Sustainability

1. Compact object headers (JEP 519)

Memory optimisation : reduces per‑object memory overhead.

Green computing : lowers heap usage and energy consumption.

Performance boost : less GC pressure, faster applications.

2. AOT compilation and startup analysis (JEP 514 & 515)

java -XX:+StartupAnalysis MyApp

3. Generational Shenandoah GC (JEP 521)

Low latency : pause times under 10 ms.

High throughput : suited for large‑heap workloads.

Adaptive tuning : automatically optimises based on workload.

Security Enhancements

1. PEM API (JEP 470)

Simplify certificate and key handling without third‑party libraries:

// Decode PEM certificate
var certificate = Pem.decodeCertificate(pemString);
// Decode PEM private key
var privateKey = Pem.decodePrivateKey(keyString);

public class PEMExample {
    public static void main(String[] args) {
        String pem = """
        -----BEGIN PUBLIC KEY-----
        MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDgjDohS0RHP395oJxciVaeks9N
        ...
        -----END PUBLIC KEY-----
        """;
        var cert = Pem.decodeCertificate(pem);
        System.out.println("Certificate algorithm: " + cert.getPublicKey().getAlgorithm());
    }
}

2. Key Derivation Function API (JEP 510)

Unified KDF interface supporting PBKDF2 and Argon2:

// PBKDF2
var key = KDF.PBKDF2.derive(secret, salt, 10000, 256);
// Argon2
var key2 = KDF.Argon2.derive(secret, salt, 65536, 2, 1, 32);

Advanced Concurrency Features

1. Scoped values (JEP 506)

Lightweight ThreadLocal alternative, ideal for virtual threads:

import java.lang.ScopedValue;
import java.util.concurrent.*;

public class ScopedUserExample {
    static final ScopedValue<String> USER = ScopedValue.newInstance();
    public static void main(String[] args) throws Exception {
        try (ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor()) {
            executor.submit(() -> ScopedValue.where(USER, "Alice").run(() -> {
                System.out.println("Thread: " + Thread.currentThread());
                System.out.println("User: " + USER.get());
            }));
            executor.submit(() -> ScopedValue.where(USER, "Bob").run(() -> {
                System.out.println("Thread: " + Thread.currentThread());
                System.out.println("User: " + USER.get());
            }));
            Thread.sleep(200);
        }
    }
}

2. Structured concurrency (JEP 505)

Treat related threads as a single unit of work:

import java.util.concurrent.StructuredTaskScope;

public class StructuredExample {
    static String fetchUser() { /* simulate */ return "Alice"; }
    static String fetchOrder() { /* simulate */ return "Order#42"; }
    public static void main(String[] args) throws Exception {
        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());
        }
    }
}

3. StableValue API (JEP 502)

Extend Optional semantics to immutable context‑stable values:

import java.lang.StableValue;

public class StableExample {
    public static void main(String[] args) {
        var greeting = StableValue.<String>of();
        String message = greeting.orElseSet(() -> "Hello from StableValue!");
        System.out.println(message);
        var cache = StableValue.<String>of();
        String cached = cache.orElseSet(() -> expensiveOperation());
    }
    private static String expensiveOperation() { return "Expensive result"; }
}

JVM Internals Improvements

1. CPU time profiling (JEP 509)

# Precise CPU usage analysis
java -XX:+CPUProfiling MyApp

2. Cooperative sampling (JEP 518)

Improved JFR sampling mechanism

Reduced performance overhead

More accurate performance data

3. Method tracing (JEP 520)

@TraceMethod
public void criticalMethod() {
    // execution automatically traced
}

Vector Computation API (JEP 508)

Java 25 introduces a powerful vector API that leverages SIMD instructions for high‑performance numeric workloads:

import jdk.incubator.vector.*;

public class VectorExample {
    public static void main(String[] args) {
        float[] left = {1f, 2f, 3f, 4f};
        float[] right = {5f, 6f, 7f, 8f};
        FloatVector a = FloatVector.fromArray(FloatVector.SPECIES_128, left, 0);
        FloatVector b = FloatVector.fromArray(FloatVector.SPECIES_128, right, 0);
        FloatVector c = a.add(b);
        float[] result = new float[FloatVector.SPECIES_128.length()];
        c.intoArray(result, 0);
        System.out.println("Vector result: " + java.util.Arrays.toString(result));
    }
}

Compilation parameters :

--enable-preview --add-modules jdk.incubator.vector