What's New in Java 21
summary
Java 21 makes several language and runtime features mainstream: Record Patterns (JEP 440) and Pattern Matching for switch (JEP 441) are standardized, and Virtual Threads from Project Loom are standard (JEP 444). String Templates and unnamed-entity syntax appear as previews (JEP 430 and unnamed preview); Structured Concurrency and Scoped Values are preview/incubating (JEP 446) to help blocking I/O; Panama brings the Foreign Function & Memory API and Vector API in incubation; ZGC adds generational garbage collection (JEP 433), with additional small API and tooling updates.
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chapters (11)
- 0:00Introduction
- 2:23Language features
- 13:51String templates preview
- 23:46Main classes and methods
- 25:09Virtual threads with Loom
- 31:10Concurrency structure
- 34:43Scope values preview
- 37:10Sequential collections
- 39:16JVM and security updates
- 42:26Project Panama and FFM
- 43:48Conclusion
