DESIGN PATTERNS ARE class- and method-level solutions to common problems in object-oriented design. If you’re an intermediate-level Java programmer who wants to become advanced or an advancedlevel Java programmer who hasn’t yet studied design patterns, this book is for you.

Design Patterns in Java™ takes a workbook approach. Each chapter focuses on a particular pattern. In addition to explaining the pattern, the chapter includes a number of challenges, each asking you to explain something or to develop code that solves a problem.

We strongly urge you to stop and work through the challenges rather than try to read this book straight through. You’ll learn more by putting in the work to do the challenges, even if it’s only a chapter or two a week.