Nat and Duncan both started programming in Java before its 1.0 release, and have 55 years of combined experience on both the JVM and other platforms. Until they discovered Kotlin in 2015 Java was their language of choice for most applications.
That changed when they fell in love with JetBrains' new creation and spread the word, first with their own colleagues and clients, then the JVM community in London, and then internationally through conferences. They have both presented at KotlinConf, where they also run a one day workshop "Refactoring to Kotlin," which forms the basis for the introductory chapters of this book.
