In this short chapter, we had a look at reactive programming, reactive systems, and reactive streams. We discussed the similarities and the differences between these that may lead to confusions. We paid special attention to Java 9 reactive streams that have practically nothing to do with Stream classes and methods.

In the second half of the chapter, we discussed a very simple example that uses reactive streams.

After reading this chapter, you have learned a lot about the Java language and programming. We did not detail all the small bits of Java, but that is not possible in a book. I dare say that there is no man (or woman for that matter) on the Earth or around it on an orbital route, wherever humans are, who knows everything about Java. We, however, know enough by now to start coding in an enterprise environment and to learn more and more on the go till we retire, or even after that. What is still left is a little bit of programming. In the previous sentence I said coding to make some distinction. Coding is not the same as programming. Coding is a technique used in the profession of programming. During the next, and last, chapter we will see the aspects of programming and how it can, and should, be done in professional manner. This is rarely a part of an introductory book, but I am happy that we could agree on this topic with the publisher. This way, you can finish the book not only with the knowledge that you learn from this book, but also with a vision, looking ahead on the road you will walk up the hillside to the top. You will know the topics, areas, and subjects that you can go on learning.