Book excerpt: This tutorial book is a collection of notes and sample codes written by the author while he was learning Java himself. Topics covered in the book include: Java language basics; execution environment; generic classes and parameterized type; generic methods and type argument inferences; enum types and constants; lambda expressions; annotation types and invocations; Java modules; execution threads and synchronization; memory management and garbage collection. Updated in 2024 (Version v8.22) with JDK 20. For latest updates and free sample chapters, visit https://www.herongyang.com/Java.