Book Image

Java 9 Dependency Injection

By : Nilang Patel, Krunal Patel
Book Image

Java 9 Dependency Injection

By: Nilang Patel, Krunal Patel

Overview of this book

Dependency Injection (DI) is a design pattern that allows us to remove the hard-coded dependencies and make our application loosely coupled, extendable, and maintainable. We can implement DI to move the dependency resolution from compile-time to runtime. This book will be your one stop guide to write loosely coupled code using the latest features of Java 9 with frameworks such as Spring 5 and Google Guice. We begin by explaining what DI is and teaching you about IoC containers. Then you’ll learn about object compositions and their role in DI. You’ll find out how to build a modular application and learn how to use DI to focus your efforts on the business logic unique to your application and let the framework handle the infrastructure work to put it all together. Moving on, you’ll gain knowledge of Java 9’s new features and modular framework and how DI works in Java 9. Next, we’ll explore Spring and Guice, the popular frameworks for DI. You’ll see how to define injection keys and configure them at the framework-specific level. After that, you’ll find out about the different types of scopes available in both popular frameworks. You’ll see how to manage dependency of cross-cutting concerns while writing applications through aspect-oriented programming. Towards the end, you’ll learn to integrate any third-party library in your DI-enabled application and explore common pitfalls and recommendations to build a solid application with the help of best practices, patterns, and anti-patterns in DI.
Table of Contents (14 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Chapter 7. IoC Patterns and Best Practices

Now that you have reached this chapter, you should know what Dependency Injection (DI) is, why it's so important, how it's projected in recent versions of Java, and how to implement it with popular frameworks, such as Spring and Google Guice, with various scopes.

It's said that knowing something is not enough until it's applied with best methodologies and practices. Knowledge is power only when it's implemented in the right manner. An improper approach may create a big mess. 

The software industry is moving toward modularity. The concepts of DI and Inversion of Control (IoC) containers were created due to this, and this is why they are so popular today. Still, many developers don't know how to utilize DI to its full potential. 

In this chapter, we will explore the real strength of DI by learning the right patterns and best practices to apply the expertise we gained in DI in previous chapters. This chapter is not meant to do anything new; instead, we...