In this chapter, we were focused on developing custom plugins for Elasticsearch. We learned how to properly set up your Maven project to be able to automatically build your Elasticsearch plugins. You saw how to develop a custom REST action plugin, and we extended Elasticsearch analysis capabilities by creating a plugin that included a custom token filter and new analyzer.

We've reached the end of the book, and we wanted to write a small summary and say a few words to the brave reader who managed to get to the end. We decided to write the second edition of Mastering Elasticsearch after writing Elasticsearch Server Second Edition. We thought that we had left a number of topics uncovered, and we wanted to write them in this book. We went from introducing Apache Lucene and Elasticsearch to querying and data handling—both on the Lucene index and the Elasticsearch level. We hope that, by now, you know how Lucene works and how Elasticsearch uses it, and you will find this knowledge worthy...