Java Clock millis()
May 20, 2019
Clock.millis gets the current millisecond instant of the clock. millis method returns the millisecond-based instant measured from 1970-01-01T00:00Z (UTC). millis is equivalent to the definition of System.currentTimeMillis(). To get an instant on the time-line, we should use Instant instead of millis. According to Java, we should use millis only in high performance use-cases where the creation of an object would be unacceptable.
Find the declaration of
Clock.millis from Java doc.
public long millis()
Now find the examples.
Example-1: We are instantiating clock with default zone and then calling
millis on this clock.
MillisDefaultZone.java
package com.concretepage;
import java.time.Clock;
public class MillisDefaultZone {
public static void main(String[] args) {
Clock clock = Clock.systemDefaultZone();
long millis = clock.millis();
System.out.println(millis);
}
}
1558345581477
millis on this clock.
MillisSpecifiedZone.java
package com.concretepage;
import java.time.Clock;
import java.time.ZoneId;
public class MillisSpecifiedZone {
public static void main(String[] args) {
ZoneId zone = ZoneId.of("Asia/Calcutta");
Clock clock = Clock.system(zone);
long millis = clock.millis();
System.out.println(millis);
}
}
1558345649093
Clock.systemUTC. It returns the clock that gives current instant using UTC time-zone. Now we are calling millis on this clock.
MillisSystemUTC.java
package com.concretepage;
import java.time.Clock;
public class MillisSystemUTC {
public static void main(String[] args) {
Clock clock = Clock.systemUTC();
long millis = clock.millis();
System.out.println(millis);
}
}
1558345693056
Clock.fixed. It returns a fixed clock that always gives the same instant. Now we are calling millis on this clock.
MillisFixed.java
package com.concretepage;
import java.time.Clock;
import java.time.Instant;
import java.time.ZoneId;
public class MillisFixed {
public static void main(String[] args) {
Instant instant = Instant.parse("2019-05-18T15:34:42.00Z");
ZoneId zoneId = ZoneId.of("Asia/Calcutta");
Clock clock = Clock.fixed(instant, zoneId);
for (int i = 1; i <= 3; i++) {
System.out.println("-----" + i + "-----");
System.out.println(clock.millis());
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
-----1----- 1558193682000 -----2----- 1558193682000 -----3----- 1558193682000
References
Java Doc: Class ClockJava Clock
