System.currentTimeMillis vs System.nanoTime

Question

Accuracy Vs. Precision

What I would like to know is whether I should use System.currentTimeMillis() or System.nanoTime()<

Answer 1

Since no one else has mentioned this…

It is not safe to compare the results of System.nanoTime() calls between different threads. Even if the events of the threads happen in a predictable order, the difference in nanoseconds can be positive or negative.

System.currentTimeMillis() is safe for use between threads.