A modular, polyglot architecture has many advantages but it also adds complexity since each incoming request typically fans out to multiple distributed services. For example, in an online store application the information on a product details page - description, price, recommendations, etc - comes from numerous services. To minimize response time and improve scalability, these services must be invoked concurrently. However, traditional concurrency mechanisms are low-level, painful to use and error-prone.

In this talk you will learn about some powerful yet easy to use abstractions for consuming web services asynchronously. We will compare the various implementations of futures that are available on the JVM. You will learn how to access web services using reactive observables (RxJava), which are asynchronous data streams. We will describe how these mechanisms let you write asynchronous code in a very straightforward, declarative fashion.