<dependencies> <dependency> <groupId>io.projectreactor</groupId> <artifactId>reactor-core</artifactId> <version>3.4.1</version> </dependency> </dependencies> import reactor.core.publisher.Flux; public class ReactorExample { public static void main(String[] args) { Flux<Integer> numbers = Flux.just(1, 2, 3, 4, 5); numbers .map(n -> n * n) .subscribe(System.out::println); } }