RxJava

RxJava (Reactive Extensions for the JVM) is a powerful library for composing asynchronous and event-based programs using observable sequences in Java. If you are an Android developer, you might be familiar with callbacks and async tasks to perform long-running operations in the background. However, handling multiple async tasks and nested callbacks can produce code that's complicated to read and maintain. To alleviate such complexities, RxJava provides tools and methods to create, transform and chain Observable sequences in a clean and declarative manner.