Chapter 12. Concurrency and Reactive Programming

In the previous chapter, we covered several Java Enhancement Proposals (JEPs) that were incorporated into the Java 9 platform. These JEPs represented a wide range of tools and updates to APIs to make developing with Java easier, with greater optimization possibilities for our Java applications. We looked at the new HTTP client, changes to Javadoc and the Doclet API, the new JavaScript parser, JAR and JRE changes, the new Java-level JVM compiler interface, the new support for TIFF images, platform logging, XML catalog support, collections, and the new platform-specific desktop features. We also looked at enhancements to method handling and the deprecation annotation.

In this chapter we will cover concurrency enhancements introduced with the Java 9 platform. Our primary focus will be the support for reactive programming, a concurrency enhancement that is provided by the Flow class API. Reactive programming is a new concept for Java 9, so we will...