Rx Java

Reactive Java:
reactivemanifesto.org
Async facde - design pattern

Java implementations:
Rx Java from Netflix
Spring 5
JSR 166 in jdk 9
WWW.reactive-streams.org
Very.X 3.0

mvnrepository.org

Observable pattern

Server is producer or observables and client is consumer or subscriber

It is one way communication where server can communicate to client but client cannot communicate to server except about subscription or unsubscription

Hot and Cold observable

We can merge multiple observables into 1 and subscribe to that new combined custom observable.