We've so far looked at some general higher level, almost common-sensical patterns, that apply to modularity in Java. Now let's dive into code. Let's look at some code patterns and strategies that can help you as you as you start designing modules and their APIs. Each of these strategies are presented with explanation about the pattern, why and when you should consider using them. Many of them have accompanying code examples for you to refer to. Some of these might be obvious. In fact, we've even applied some of the patterns when building the sample address book application we've worked on in this book. I hope this consolidated list provides you with a good reference to these patterns when designing and building modular applications.