From this whirlwind tour of Reactive Programming, you should be proficient in writing reactive applications on the JVM. Your programming skills now include how to use the Vert.x core API to write asynchronous and non-blocking services. You have also learned how to combine the Observable pattern with streams or asynchronous results using the Vert.x Reactive API. Then, we quickly explored the last Vert.x paradigm, Vert.x Axle, which allows different beans to interact using asynchronous messages and enforces loose coupling. Finally, we applied a reactive API to access a relational database using the PostgreSQL client extension for Vert.x.
Although you've gotten to grips with the Reactive Programming API, note that much of its power can only be unleashed when building real-time data pipelines and streaming data. We will cover these in the next chapter.