Not resuming Virtual Threads?

[Ron Pressler]

That could happen if you write your own scheduler or some synchronization
construct (like a lock). In that case, the virtual thread (and associated
continuation) will be garbage-collected. From a semantics perspective, it
is the same as sleeping forever. Java makes no liveness guarantees so this
does not violate any existing ones.

But yeah, this can only happen as a result of a bug in a scheduler or a 
synchronization construct, and certainly inadvisable to do intentionally.

— Ron


On 2 July 2020 at 18:45:55, Johannes Kuhn (info at j-kuhn.de) wrote:

After playing around with Virtual Threads a bit, I got to the question:  
What happens if you don't resume a virtual thread?  

This could be either done by accident - single thread carrier, that  
waits on an other virtual thread that should be executed on the same  
carrier, but the virtual thread is pinned -  
or on purpose, like not iterating over all elements in my Generator  
example[1]. Or closing the executor once you got an answer.  

What happens with those Continuations? Can they be garbage collected?  
What about held locks? How is this different from Thread.suspend?  
Isn't that inherently dangerous?  

Just trying to get a better understanding of the model here.  

- Johannes  

[1]: https://gist.github.com/DasBrain/abfdaa44b44d898f5d3c3888619eb49b