What’s New in Java 17? A Deep Dive into Its Key Features

JDK/Java 16 was officially GA in March as a short‑term support release with six months of updates. JDK/Java 17, a long‑term support (LTS) version, is scheduled for release on 14 September and will receive several years of support.

JDK 17 is now in the second and final release‑candidate phase (RC), the latest being build 35.

According to InfoWorld, OpenJDK 17 introduces the following notable features:

Context‑specific deserialization filters that let applications choose filters per serialization operation via a JVM‑wide filter factory.

Restored always‑strict floating‑point semantics, ensuring consistent strict behavior matching the original Java 1.2 semantics.

Deprecation of the Security Manager, slated for removal in future releases, with discussion of alternative APIs for its narrow use cases.

Preview of switch pattern matching, extending the pattern language for switch expressions and statements, adding guarded and parenthesized patterns.

Strong encapsulation of internal JDK APIs (e.g., sun.misc.Unsafe) without command‑line relax options, improving security and maintainability.

Removal of the RMI activation mechanism, which was deprecated in JDK 15.

Incubator stage for foreign function and memory APIs, enabling interoperation with native code and data.

Vector API (incubator) enhancements, providing a performant way to express vector computations that compile to optimal CPU instructions.

Sealed classes and interfaces to restrict which classes or interfaces may extend or implement them.

Removal of experimental AOT and JIT compilers, keeping the JVM compiler interface for external compilers.

Porting of the JDK to macOS/AArch64 in response to Apple’s transition to Apple Silicon.

Deprecation of the Applet API, reflecting the disappearance of Java browser plugins.

New rendering pipeline for macOS using Apple’s Metal API as a replacement for the deprecated OpenGL pipeline.

Enhanced pseudo‑random number generator framework with new RandomGenerator interfaces, additional algorithms, and support for streams and split‑able generators.

JDK 17 LTS releases occur every three years; the previous LTS version, JDK 11, was released in September 2018.

For more details, visit https://jdk.java.net/17/.