How do I get milliseconds from epoch (1970-01-01) in Java?

Question

I need to get the number of milliseconds from 1970-01-01 UTC until now UTC in Java.

I would also like to be able to get the number of milliseconds from 1970-01-01 UTC to any other UTC date time.

Answer 1

How about System.currentTimeMillis()?

From the JavaDoc:

Returns: the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC

Java 8 introduces the java.time framework, particularly the Instant class which "...models a ... point on the time-line...":

long now = Instant.now().toEpochMilli(); 

Returns: the number of milliseconds since the epoch of 1970-01-01T00:00:00Z -- i.e. pretty much the same as above :-)

Cheers,

Answer 2

java.time

Using the java.time framework built into Java 8 and later.

import java.time.Instant;  Instant.now().toEpochMilli(); //Long = 1450879900184 Instant.now().getEpochSecond(); //Long = 1450879900 

This works in UTC because Instant.now() is really call to Clock.systemUTC().instant()

https://docs.oracle.com/javase/8/docs/api/java/time/Instant.html