In this lesson, you will learn how to create an observable source based upon primitive types and objects through the use of the `Observable.just` operator. You will learn how to create the source and subscribe to it so that you can receive the values. You'll learn about the terminal events, `onComplete` and `onError` and when they're called. The lesson wraps up with a demonstration of how the `just` operator will terminate upon encountering an error in the stream of items. This example is demonstrated in RxJava 2 with Consumers and Actions and is written in Kotlin.