You're confusing the thread pinning problem with "breakage". The problem with some synchronized blocks is that they lead to thread pinning for the duration of t

You're confusing the thread pinning problem with "breakage". The problem with some synchronized blocks is that they lead to thread pinning for the duration of the lock. Why is thread pinning bad? Because it means that if one core is idle, but all the threads are pinned to a specific core, you won't get full CPU utilisation. This undermines the performance benefit of virtual threads, because they are supposed to be schedulable via work stealing.