Java's take on monitors was definitely not great, and people were emulating mutexes with them even in the language's earliest days. Still there are a lot of th

Java's take on monitors was definitely not great, and people were emulating mutexes with them even in the language's earliest days. Still there are a lot of things that can go wrong with mutexes: forgetting to unlock in the case of exceptions, priority inversion, recursive locking, deadlock, needlessly high contention, etc. Java has had an excellent concurrency runtime with abstractions that are typically a better fit than a bare mutex for over 20 years now (c.f. Doug Lea). Synchronized still exists, because of Java's excellent backwards compatibility.