Acknowledgement is the section of a book that everybody ignores by turning the pages. This time, this section is a bit different. I will mention a few people and their roles in the making of this book but, at the same time, I will explain why and how it is important to rely on people, being a software developer.Doing professional work is not possible without having a life. It is quite obvious if you take that literally, but it is just as true figuratively. If you do not find the balance between your personal and professional life, you will burn out and will not operate professionally. This is the place to mention my family, my parents whom I am lucky to still have around, my wife, and my already adult kids who never stopped believing in me being able to do this work, who know more than well what a hypocrite I am, advocating personal-professional life balance, and who continually pushed me closer to this equilibrium point in life so that I could keep performing professionally.For professional work, coworkers are almost as important as family support. It is important that you support your colleagues as much as you ask them for their support. You learn a lot from books and from experience, but you learn the most from other people. Pay attention to senior developers. You can, however, learn just as much from juniors. No matter how ace you are, from time to time, a rookie may shed light on a topic. During the years, I learned a lot from juniors who brought a fresh view to the table, asking shocking questions that were absolutely valid. I cannot name each and every junior who aided my work with fresh out-of-the-box thinking.I can, and should, however, name some peer professionals who actively participated in the creation of this book with their advice, discussions, and suggestions.I should certainly mention Károly Oláh who was very enthusiastic about my project, and he represented, supported, and encouraged the idea inside EPAM systems. He actively discussed with the upper management that the support for writing a book well fits the innovation line and development of the company, and the people who work together. Without the official support from the company providing extra time for the task, I would not have been able to create this book.Good company attracts good people who are clever and also good to work with. I had many discussions about the book, topics, and how to explain certain aspects with my fellow EPAMers: Krisztián Sallai, Peter Fodor, Sándor Szilágyi, Mantas Aleknavicius, Gábor Lénard, and many others.I will separately mention István Attila Kovács from our Budapest office with whom I discussed Chapter 5 in detail, and who gave me very valuable feedback about the topic. If he does not know something about Java parallel computing, then that something does not exist.As a summary and takeaway for the patient reader who read this section till the end, technology, knowledge, skills, and experience are extremely important for being a professional Java 9 developer, but it is the people who really matter.