import io.reactivex.rxjava3.core.Observable;

import java.util.concurrent.TimeUnit;

public class Ch1_3 {

public static void main(String[] args) {

Observable<Long> secondIntervals =

Observable.interval(1, TimeUnit.SECONDS);

secondIntervals.subscribe(s -> System.out.println(s));

/* Hold main thread for 5 seconds

so Observable above has chance to fire */

sleep(5000);

}

private static void sleep(long millis) {

try {

Thread.sleep(millis);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}