Initial blog post I found, follow the links
netflix reactive rest Youtube - SpringDeveloper Futures and Rx Observables: powerful abstractions for consuming web services asynchronously
Design pattern to handle an asynchronous response in Java
reactive streams api for java reactive manifesto spring reactor rc1 Building Microservices with Spring Boot Building Microservices with Spring Boot and Apache
Comparison of different concurrency models: Actors, CSP, Disruptor and Threads Java Concurrency: Learing from Node.js, Scala, Dart and Go