Program
public class DateNanoSeconds {
public static void main(String[] args) {
System.out.print("time in nanoseconds = ");
System.out.println(System.nanoTime());
}
}Output
time in nanoseconds = 1130846920837400
Description
public static long nanoTime()
Returns the current value of the running Java Virtual Machine’s high-resolution time source, in nanoseconds.
This method can only be used to measure elapsed time and is not related to any other notion of system or wall-clock time. The value returned represents nanoseconds since some fixed but arbitrary origin time (perhaps in the future, so values may be negative). The same origin is used by all invocations of this method in an instance of a Java virtual machine; other virtual machine instances are likely to use a different origin.
This method provides nanosecond precision, but not necessarily nanosecond resolution (that is, how frequently the value changes) – no guarantees are made except that the resolution is at least as good as that of currentTimeMillis().
Differences in successive calls that span greater than approximately 292 years (263 nanoseconds) will not correctly compute elapsed time due to numerical overflow.
The values returned by this method become meaningful only when the difference between two such values, obtained within the same instance of a Java virtual machine, is computed.
For example, to measure how long some code takes to execute:
long startTime = System.nanoTime();
// … the code being measured …
long estimatedTime = System.nanoTime() – startTime;
To compare two nanoTime values
long t0 = System.nanoTime();
…
long t1 = System.nanoTime();
one should use t1 – t0 < 0, not t1 < t0, because of the possibility of numerical overflow.
Returns:
the current value of the running Java Virtual Machine’s high-resolution time source, in nanoseconds
