There are several automated build systems available, but the two most mainstream options are Gradle and Maven. Gradle is somewhat a successor to Maven and is especially the go-to build automation solution for Android development. If you are not familiar with Gradle and would like to learn how to use it, check out the Gradle Getting Started guide (https://gradle.org/getting-started-gradle-java/).

There are also several decent books that cover Gradle in varying degrees of depth, which you can find at https://gradle.org/books/. The following screenshot displays the The Central Repository page showing how to set up RxJava 2.0.2 for Gradle:

You can find the latest Gradle configuration code and copy it into your Gradle script

In your build.gradle script, ensure that you have declared mavenCentral() as one of your repositories. Type in or paste that dependency line compile 'io.reactivex.rxjava2:rxjava:x.y.z', where x.y.z is the version number you want to use, as shown in the following code snippet:

apply plugin: 'java'

sourceCompatibility = 1.8

repositories {
      mavenCentral()
}

dependencies {
      compile 'io.reactivex.rxjava2:rxjava:x.y.z'
}

Build your Gradle project and you should be good to go! You will then have RxJava and its types available for use in your project.

You also have the option to use Maven, and you can view the appropriate configuration in The Central Repository by selecting the Apache Maven configuration information, as shown in the following screenshot:

Select and then copy the Apache Maven configuration

You can then copy and paste the <dependency> block containing the RxJava configuration and paste it inside a  <dependencies>block in your pom.xml file. Rebuild your project, and you should now have RxJava set up as a dependency. The x.y.z version number corresponds to the desired RxJava version that you want to use:

<project>
  <modelVersion>4.0.0</modelVersion>
    <groupId>org.nield</groupId>
    <artifactId>mavenrxtest</artifactId>
    <version>1.0</version>
  <dependencies>
    <dependency>
     <groupId>io.reactivex.rxjava2</groupId>
     <artifactId>rxjava</artifactId>
     <version>x.y.z</version>
    </dependency>
  </dependencies>
</project>