This book is a Java desktop reference that will serve you well if you keep it handy on your desk as you program in Java. Part 1 of this book provides a brief but not superficial introduction to the Java programming language and describes the basic properties of the Java runtime system. Part 11 explains the concepts using examples from the most important APIs. Although this book covers Java 11, we, the authors, are fully aware that it is not yet widely adopted, and therefore emphasize where appropriate that a particular feature was implemented in Java 8, 9, or 10. In all examples The books in this book use Java 11 syntax, including the var keyword and lambda expressions.