Are "atomic" and "synchronous" synonyms in programming?

Question

Do "atomic" and "synchronous" mean the same thing or are there some minute differences?

Looking at the answers to this question, I think the answer to my question is yes, they're synonyms. Are the following true in general?

• a synchronous operation will complete before the next operation starts
• an atomic operation is the same as a synchronous operation
• an asynchronous operation will complete at some point before or after the next operation starts

Answer 1

Not quite the same. An atomic operation is one that can't be subdivided into smaller parts. So, in Java, assigning to an int is atomic: nothing can interrupt it, it either completes or doesn't.

A synchronous operation is one that simulates being atomic through some programming mechanism you invoke using the synchronized keyword. The implementation of that can vary.So in a synchronized block, the run time system enforces what's called a critical region in which only one thread of control can pass at the same time.