[nimish]

All that says is the Java runtime will suspend on blocking IO, not that it _only_ suspends on blocking IO.

> what they're intended for

Java prides itself on careful and deliberate changes to eliminate foot guns, but this seems like a pretty major restriction. Usually these kinds of cooperative threads are called fibers or something else to distinguish them from truly preempt-able threads.

Expecting developers to read the minutiae of documentation (there's another restriction around synchronized blocks) is a fool's errand TBH. Principle of least surprise, etc.