[MBCook]

c3p0 appears to have been working under the assumption that their threads can always run when whatever they’re waiting on is done. Their only dependency is the OS giving them cycles.

Virtual threads changed the contract a little bit. Now one virtual thread running certain code can prevent a different virtual thread from ever getting any cycles even though they are not dependent on each other in the Java code. It’s a side effect of the current Java implementation.

The rules changed, and it tripped up c3p0. Unless they explicitly said somewhere that they were completely ready for virtual threads I’m not sure anyone is at fault here.