Summary

This chapter introduced you to functional programming by explaining and demonstrating the concept of functional interfaces and Lambda expressions. The overview of standard functional interfaces that comes with JDK helps you to avoid writing custom code, while the method reference notation allows you to write well-structured code that is easy to understand and maintain.

Now, you are able to write functions and use them for Lambda expressions in order to pass them as a method parameter.

In the next chapter, we will talk about data stream processing. We will define what data streams are, and look at how to process their data and how to chain stream operations in a pipeline. Specifically, we will discuss the streams’ initialization and operations (methods), how to connect them in a fluent style, and how to create parallel streams.