Cay S. Horstmann is principal author of Core Java, Volumes I and II, Twelfth Edition (Pearson, 2022), and author of Modern JavaScript for the Impatient (Addison-Wesley, 2020) and Scala for the Impatient, Second Edition (Addison-Wesley, 2016). He has written more than a dozen other books for professional programmers and computer science students. He is professor emeritus of computer science at San Jose State University and a Java Champion.