The Observable design pattern is found in many Java APIs and in reactive programming. Here's an introduction to the timeless Observable pattern in Java.

RxJava is a Java VM implementation of Reactive Extensions: a library for composing asynchronous and event-based programs by using observable sequences. It extends the observer pattern to support ...

Free, hosted Observable notebooks provide an interactive experience and lots of free, open-source Observable JS code you can reuse and learn from. Here's how to get started.