Java 21 Features

Language Features

Record Patterns (finalized)

Deconstruct records directly in pattern matching.

Pattern Matching for switch (finalized)

Enables type patterns and guarded patterns in switch.

String Templates (preview)

Simplifies string interpolation with template expressions.

Unnamed Classes and Instance main Methods

Simplifies Java for beginner-friendly code (preview).

Scoped Values

Safe, efficient alternatives to thread-local variables.

Virtual Threads & Concurrency

Virtual Threads (finalized)

Lightweight threads to simplify high-throughput concurrent programming.

Structured Concurrency (preview)

Simplifies managing concurrent tasks in structured blocks.

Libraries & APIs

Sequenced Collections

Adds consistent ordering APIs to collections (e.g., first(), last()).

Key Encapsulation Mechanism (KEM) APIs

Adds new encryption APIs for modern cryptographic use cases.

Performance / VM

Generational ZGC

Adds generation support to ZGC for better memory performance.

Deprecations

Deprecate Windows 32-bit x86 Port

Marks the 32-bit Windows port for future removal.