You will likely not use schedulers like this in isolation as we are about to do in this section. You are more likely to use them with observeOn() and subscribeOn(). But here is how they work in isolation outside of an Rx context.

A Scheduler is RxJava's abstraction for pooling threads and scheduling tasks to be executed by them. These tasks may be executed immediately, delayed, or repeated periodically depending on which of its execution methods are called. These execution methods are scheduleDirect() and schedulePeriodicallyDirect(), which have a few overloads. Below, we use the computation Scheduler to execute an immediate task, a delayed task, and a repeated task as shown below:

import io.reactivex.Scheduler;
import io.reactivex.schedulers.Schedulers;

import java.util.concurrent.TimeUnit;

public class Launcher {

    public static void main(String[...