[pron]

> Are virtual threads preemptable?

Yes, but the preemption operation is not currently publicly exposed. We're considering whether and how to expose it.

> I wonder how many devs will spawn tasks using the default executor and then wonder why things aren't working out so well? Will there be tooling to help identify such issues?

What those issues would actually be, in practice, is still unclear, hence our reluctance to expose forced preemption. People rely on OS time-sharing (what you call preemption) inside applications far less than they think. No scheduling algorithm can make a program that requires more processing resources than available to run well.