What’s New in Java 25? Simplified Syntax, AI Boosts, and Performance Gains

Oracle has released JDK 25, the first long‑term support (LTS) version since JDK 21, bringing a range of new features aimed at simplifying Java for beginners and enhancing performance.

Key additions include compact source files that allow a “Hello World” program without a class declaration, concise module‑import statements, and more flexible constructors.

Each LTS release is significant for enterprises that prefer long‑term supported versions.

Recent JDK releases (22‑24) introduced the Foreign Function & Memory (FFM) API, which will eventually replace JNI for native inter‑operation.

JDK 25 is available as an OpenJDK build under the GPL license.

Simplified “Hello World” Example

void main() {
    IO.println("Hello World!");
}

The new syntax removes the need for a class and a verbose public static void main(String[] args) method, and the streamlined module‑import feature lets developers import multiple packages with a single statement.

Memory Efficiency Improvements

Compact object headers reduce the object header size from 12‑16 bytes to 8 bytes, cutting heap usage by up to 22 % in benchmarks and lowering CPU time by about 8 %.

AI‑Related Features

Pattern matching, instanceof, and enhanced switch improve integration of AI‑related business logic.

Module‑import declarations simplify combining AI inference libraries and services.

Vector API, widely used for AI inference and computation.

Structured concurrency enables running multiple AI tasks concurrently with better reliability.

Scoped values support efficient sharing of immutable data across threads.

Other Notable Enhancements

JFR CPU‑time analysis for more accurate performance profiling on Linux.

PEM‑encoded encryption objects API for easier key and certificate handling.

Shenandoah generational garbage collector promoted to a standard feature.

Improved ahead‑of‑time (AOT) compilation for faster startup.

Enhanced pattern matching for primitive types.

Vector API tenth iteration with performance optimisations.

Key‑derivation function API supporting HMAC, Argon2 and post‑quantum algorithms.

Structured concurrency preview 5 for better observability and error handling.

Flexible constructor bodies allowing statements before super(...) or this(...).

Module‑import declaration for bulk package imports.

Simplified source files and instance main methods for small applications.

Stable values for one‑time immutable data initialisation.

Removal of 32‑bit x86 port to reduce maintenance overhead.

Overall, developers praise Java’s stability and ubiquity, though some note legacy code complexity and the high cost of commercial licences for organisations that cannot use the open‑source GPL builds.