Java 25 (JDK 25) — Official New Features

Java 25 (GA March 2025) arrives as an LTS release packed with performance, developer-productivity, and observability improvements.
Here’s a fast, complete look at what’s actually shipped — with short code examples and plain-English takeaways.

Language Updates

1Primitive Patterns in instanceof & switch (JEP 507 – Preview)

Pattern matching now supports primitive types directly.

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1switch (obj) {
2  case int i    -> System.out.println("int: " + i);
3  case double d -> System.out.println("double: " + d);
4  default       -> System.out.println("unknown");
5}

Makes code simpler when working with numeric or JSON-like data.

2Module Import Declarations (JEP 511 – Final)

You can now import entire modules in one line:

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1import module java.base;
2List<String> list = List.of("A", "B");

✅ Great for learning and scripting — no more dozens of import lines.

Compact Source Files (JEP 512 – Final)

Run single-file programs without boilerplate:

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1IO.println("Hello, Java 25!");

✅ Perfect for scripting, teaching, or DevOps utilities.

Flexible Constructor Bodies (JEP 513 – Final)

Constructors can validate before

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1class User {
2  User(String name) {
3    if (name == null) throw new IllegalArgumentException();
4    super();
5  }
6}

✅ Enables early validation and cleaner class design.

Libraries & APIs

Scoped Values (JEP 506 – Final)

Safer alternative to ThreadLocal:

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1try (ScopedValue.where(UserContext.KEY, user)) {
2  processRequest();
3}

✅ Immutable, thread-safe, and ideal for structured concurrency or virtual threads.

Structured Concurrency (JEP 505 – Preview)

Treat multiple tasks as one unit:

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1try (var scope = new StructuredTaskScope.ShutdownOnFailure()) {
2  var a = scope.fork(() -> fetchA());
3  var b = scope.fork(() -> fetchB());
4  scope.join();
5  return combine(a.resultNow(), b.resultNow());
6}

✅ Easier parallel programming with proper cancellation and error handling.

Stable Values (JEP 502 – Preview)

Immutable objects treated like constants, enabling lazy initialization + optimization.

✅ Boosts startup performance for large data structures.

Vector API (10th Incubator – JEP 508)

Continued SIMD enhancements for numeric & AI workloads.

✅ Write Java that runs like native SIMD code — great for ML inference and analytics.

PEM Encoding & KDF API (JEP 470 & 510 – Final)

New standard APIs for cryptography:

• PEMEncoder/Decoder for certificates & keys
• KDF API for deriving secure keys (e.g. HKDF, Argon2)

✅ Easier integration with OpenSSL, SSH, and hybrid encryption systems.

JVM & Runtime

• Compact Object Headers (JEP 519) → finalized, ~22% less heap.
• Generational Shenandoah (JEP 521) → production-ready GC with shorter pauses.
• Removed 32-bit x86 Port (JEP 503) → modern 64-bit only builds.

Real performance + memory gains out of the box.

Tools & Monitoring

AOT Ergonomics & Profiling (JEP 514 & 515)

AOT compilation now works in one step:

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1java -XX:AOTCacheOutput=app.aot -jar app.jar

✅ Faster startup + optional profiling baked into the cache.

JFR Upgrades (JEP 509 / 518 / 520)

Flight Recorder gains:

• CPU-time sampling for accurate native usage
• Cooperative sampling → no more unsafe stack walking
• Method-level tracing → record exact call counts & durations

✅ Better profiling, fewer crashes, richer insights.

Summary

Java 25 modernizes the platform while keeping stability:

• ✅ Cleaner syntax
• ✅ Faster startup
• ✅ Richer profiling
• ✅ Leaner runtime

If you’re on Java 17 or 21 LTS, Java 25 is the upgrade worth testing today.

💡 Tip: Use --enable-preview to explore JEP 507 and JEP 505.
Follow openjdk.org/projects/jdk/25 for reference.