If you're using Gradle, add the following dependency:

    compile 'io.projectreactor:reactor-core:3.1.1.RELEASE' 

If you're using Maven, add the following dependency to the POM.xml file:

    <dependency> 
      <groupId>io.projectreactor</groupId> 
      <artifactId>reactor-core</artifactId> 
      <version>3.1.1.RELEASE</version> 
    </dependency>

So, as we're done with adding Reactor Core to our project, let's get started with Flux and Mono, producers in Reactor.