That statement was oversimplified. Its funny I've actually hit head on people who didnt understand "critical sections" and such and just added synchronized everywhere and even that didnt help because they were locking an independent object vs a shared object that had to be locked in order to create a critical section.

So yea read up on multithreading, its extremely important to know, but hey my friend worked 4 yrs in .net and just started learning multithreading. So its not always needed.