Virtual Threads: Ushering in a New Era of Concurrency
summary
Project Loom adds lightweight virtual threads in JDK 21 (JEPs 425, 436, 444) that let Java run millions of concurrent tasks cheaply: demos create 10 million virtual threads and replace pools by Executors.newVirtualThreadPerTaskExecutor or Thread.ofVirtual().start, cutting a 10k-task sleep-based benchmark to ~63 ms (claimed ~99% speedup). Virtual threads sit on a small set of platform carriers so CPU-bound work still uses platform threads; beware pinning by synchronized/native calls and use ReentrantLock or JFR to diagnose.
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chapters (8)
- 0:00Introduction to virtual threads
- 10:48Limitations of traditional threads
- 20:07Creating and using virtual threads
- 27:59How virtual threads work under the hood
- 33:50Pitfalls and best practices with virtual threads
- 40:23When to use virtual vs platform threads
- 47:23Virtual threads vs reactive programming
- 51:42Closing and resources
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