Java™ SE Development Kit 25

JDK 25

JDK 25 reached General Availability on 16 September 2025. 

Production-ready binaries under the GPL are available from Oracle

JDK 25 is a long-term support (LTS) release from most vendors. For a complete list of the JEPs integrated since the previous LTS release, JDK 21, please see here.

Binaries from openJDK are available here:

https://jdk.java.net/25/

https://openjdk.org/projects/jdk/25/

Release notes from Oracle

https://www.oracle.com/java/technologies/javase/25-relnote-issues.html

🚀 What JDK 25 brings

Major new additions / enhancements:

• Compact Object Headers (JEP 519): reduces object header size for many objects on 64-bit platforms → lower memory and better heap density. Java Code Geeks+1

• Scoped Values (JEP 506): a safer/more efficient alternative to ThreadLocal for context propagation, especially with virtual threads. Java Tech Online+1

• Flexible Constructor Bodies (JEP 513): allows code before super()/this() in constructors. HappyCoders.eu

• Compact Source Files & Instance Main Methods (JEP 512): lets you write simpler top-level code without class boilerplate (good for learning, quick scripts). Java Tech Online

• Primitive Types in Patterns (JEP 507, preview): pattern matching now supports primitives (int, double, etc.). Baeldung on Kotlin+1

• Performance & runtime enhancements:

  • Generational Shenandoah GC (JEP 521) becomes supported. Java Code Geeks

  • JDK Flight Recorder (JFR) improvements: better CPU-time profiling, method timing & tracing. Java Tech Online+1

• Security / cryptography: Key Derivation Function API (JEP 510) finalised to support modern cryptograpic workflows. JDK Builds

• Module import declarations (JEP 511): easier modular code reuse/imports. Java Tech Online

• JDK 25 is also an LTS release. OpenJDK+1

What this means for you:

• Significant runtime and memory improvements: if you manage large scale Java services you’ll likely benefit from Compact Object Headers, improved GC, and profiling tools.

• More expressive language features continue to expand.

• Better support for modern concurrency/context propagation (via Scoped Values) which ties into virtual threads.

• If you build frameworks or libraries, features like Module Import Declarations may reduce boilerplate for users.

• The migration path from 21 → 25 is relevant because many new features are production-ready (no longer preview) so you may want to plan early.

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📋 Side-by-side comparison

Category	JDK 21	JDK 25
Status	LTS (Sep 2023)	LTS (Sep 2025)
Major concurrency addition	Virtual threads finalised HowToDoInJava+1	Scoped Values finalised; further concurrency ecosystem improvements Java Code Geeks+1
Language expressiveness	Record patterns, switch pattern matching, sequenced collections Baeldung on Kotlin	Adds flexible constructors, primitive types in patterns (preview), compact source files Java Tech Online
Performance / runtime	Improved JVM generally, new APIs	Compact object headers, generational Shenandoah GC, better profiling tools Java Code Geeks
Cryptography/security	KEM API introduced InfoWorld	Key Derivation Function API final, better security readiness JDK Builds
Library & tooling	Good improvements	Module import declarations, further enhancements in tooling and observability Java Tech Online
Preview features status	Many preview (string templates, unnamed classes) Baeldung on Kotlin	Some features still preview/incubator (primitive types in patterns) Java Tech Online
Migration / production readiness	Very production-ready at release	Already production-ready for many features, but some still in preview – evaluate accordingly