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Java / Java 21 Virtual Threads Interview questions

How is a virtual thread mounted onto a carrier thread?

Mounting is the act of a carrier thread picking up a virtual thread's continuation and executing its code. Unmounting is the reverse: detaching that continuation so the carrier is free for other work.

When the scheduler assigns a runnable virtual thread to an idle carrier, the JVM restores (thaws) the virtual thread's saved stack state onto that carrier and execution continues from where it left off.

Crucially, a virtual thread isn't guaranteed to resume on the same carrier thread it started on - each mount/unmount cycle can land it on a different one, which is fine since a virtual thread's identity is independent of any particular OS thread.

Mounting refers to:
After being unmounted and later resumed, a virtual thread:

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