Synchronization vs Lock

Question

java.util.concurrent API provides a class called as Lock, which would basically serialize the control in order to access the critical resource. It gives method such as park() and unpark().

We can do similar things if we can use synchronized keyword and using wait() and notify() notifyAll() methods.

I am wondering which one of these is better in practice and why?

Answer 1

You can achieve everything the utilities in java.util.concurrent do with the low-level primitives like synchronized, volatile, or wait / notify

However, concurrency is tricky, and most people get at least some parts of it wrong, making their code either incorrect or inefficient (or both).

The concurrent API provides a higher-level approach, which is easier (and as such safer) to use. In a nutshell, you should not need to use synchronized, volatile, wait, notify directly anymore.

The Lock class itself is on the lower-level side of this toolbox, you may not even need to use that directly either (you can use Queues and Semaphore and stuff, etc, most of the time).