Java Generics and Collections, 2nd Edition

Part I. Generics

Generics are a powerful, and sometimes controversial, feature of the Java programming language. This part of the book describes generics, using the Collections Framework as a source of examples. A comprehensive introduction to the Collections Framework appears in the second part of the book.

The first four chapters focus on the fundamentals of generics. Chapter 1 gives an overview of generic types and methods. Chapter 2 reviews how subtyping works and explains how wildcards let you use subtyping in connection with generics. Chapter 3 describes how generics work with the Comparable interface, which requires a notion of bounds on type variables. Chapter 4 looks at how generics work with various declarations, including constructors, static members, and nested classes. Once you have these four chapters under your belt, you will be able to use generics effectively in most basic situations.

The next three chapters treat advanced topics. Chapter 5 explains how the same design that leads to ease of evolution also necessarily leads to a few rough edges in the treatment of casts, exceptions, and arrays. The fit between generics and arrays is the worst rough corner of the language, and we formulate two principles to help you work around the problems. Chapter 6 explains features that relate generics and reflection, including the type Class<T> and additions to the Java library that support reflection of generic types. Chapter 7 contains advice on how to use generics effectively ...