Reactive and Asynchronous Java

  • 2 Days
  • Intermediate
  • Virtual | Classroom
  • £ On Request

Develop high performance, reactive Java applications using the latest concurrency techniques, with Java Champion Richard Warburton and Raoul-Gabriel Urma

Book For My Team

Your team will learn...

Understand various models of concurrency and asynchronous programming

Explore and develop applications using the Actor model and Akka

Learn how develop and test Promises and CompletableFutures

Develop reactive applications using RxJava

About the Trainers

Raoul-Gabriel Urma

Raoul-Gabriel Urma obtained a PhD in Computer Science from the University of Cambridge. He is co-author of the international bestselling book Java 8 in Action which sold over 20,000 copies in the world. Raoul is a regular conference speakers and delivered over 50 technical talks at international conferences. He has worked for large companies such as Google, eBay, Oracle, and Goldman Sachs, as well as for several startup projects.

Richard Warburton

Richard Warburton is an empirical technologist and solver of deep-dive technical problems. Recently he has written a book on Java 8 Lambdas for O’Reilly. He’s worked as a developer in many areas including Statistical Analytics, Static Analysis, Compilers and Networking. He is a leader in the London Java Community and runs OpenJDK Hackdays. Richard is also a known conference speaker, having talked at JavaOne, Devoxx, JFokus, DevoxxUK, Geecon, JAX London and Codemotion. He has obtained a PhD in Computer Science from the University of Warwick.


Reactive and Asynchronous applications are growing in popularity, but what is the best way to build them? This course teaches you how to apply the latest concurrency techniques to develop state of the art Java applications. With the rise of Microservices and Service Oriented Architectures, asynchronous concurrency is now critical to day-to-day Java development.

We start off by reviewing the differences between asynchronous and synchronous programming. You then build upon this theory by refactoring a project using different modern concurrency techniques including promises using Java 8’s CompletableFuture, actors using Akka and reactive streams using RxJava. You’ll learn the good, the bad and the ugly between these approaches in terms of compositionality, testability and simplicity.


Asynchronous vs Synchronous Programming

  • Servlets
  • Asynchronous Servlets (3.0) and Spring
  • Why use asynchronous communications?
  • Solving the C10K Problem and the Microservices Performance problem
  • The full stack - from application right down to the OS
  • Timeouts
  • The Reactive Manifesto
  • Models of Concurrency: Event Based, Promises, The Actor Model, Reactive Streams

Promises using CompletableFutures

  • Executor and Future
  • CompletableFuture
  • Composition patterns
  • Asynchronous Timeouts
  • Exception handling
  • Testing

The Actor Model with Akka

  • Why and when would you use Actors?
  • What are Actors?
  • Using Akka
  • Testing actors

Reactive Streams with RxJava

  • Introducing Reactive Streams
  • Using RxJava
  • Pull vs. Push models
  • Threading and Back Pressure
  • Connecting Reactive streams to databases and web sockets
  • Java 9 Flow API
  • Alternative Reactive Stream Implementations


  • Code examples and exercises will be written in Java 8 so a basic knowledge of Java 8 is required
Garth Gilmour
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Ryan Adams

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For a breakdown of what to expect in our training, check out our training overview page.

Excellent course - packed full of information and I'm looking forward to delving deeper in my own time.

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