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Java time Clock fixed


The method java.time.Clock.fixed() returns a clock that always returns the same time. This type of clock is mainly useful in testing.

Method signature

The signature of the java.time.Clock.fixed() method is as follows:

public static Clock fixed(Instant fixedInstant, ZoneId zone)

The method is available since Java 8.


  • Instant fixedInstant: the instant to use, not null
  • ZoneId zone: the time-zone that will be used to convert the instant to date-time, not null

Return value

Returns a clock that always returns the same time.


The method throws no exceptions.

Example usage

In the following code we use java.time.Clock.fixed():


import java.time.Clock;
import java.time.ZoneId;
import java.util.concurrent.TimeUnit;

import static java.time.Instant.ofEpochMilli;

public class ClockExample {

    public static void main(String[] args) {
        Clock clock = Clock.fixed(
        System.out.println("Current millis: " + clock.millis());
        try {
            // wait for a while:
        } catch (InterruptedException e) {
        System.out.println("Current millis: " + clock.millis());

The above code produces the following output:

Current millis: 0
Current millis: 0
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