RxJava vs FF4J: What are the differences?
What is RxJava? Reactive Extensions for the JVM. A library for composing asynchronous and event-based programs by using observable sequences for the Java VM.
What is FF4J? Feature Flags for Java made easy. It is an implementation of Feature Toggle pattern : Enable and disable features or your applications at runtime thanks to dedicated web console, REST API, JMX or even CLI. It handle also properties and provide generic interfaces.
RxJava can be classified as a tool in the "Java Tools" category, while FF4J is grouped under "Feature Flags Management".
RxJava is an open source tool with 43.2K GitHub stars and 7.21K GitHub forks. Here's a link to RxJava's open source repository on GitHub.