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

A brief introduction to Spring framework


Spring is a lightweight and open source enterprise framework created way back in 2003. Modularity is the heart of Spring framework. Because of this, Spring can be used from the presentation layer to the persistence layer.

The good thing is, Spring doesn't force you to use Spring in all layers. For example, if you use Spring in the persistence layer, you are free to use any other framework in presentation of the controller layer.

Another good part of Spring is its Plain Old Java Object (POJO) model-based framework. Unlike other frameworks, Spring doesn't force your class to extend or implement any base class or interface of Spring API; however, Spring does provide a set of classes to use other frameworks, such as ORM frameworks, logging framework, Quartz timers, and other third-party libraries, which will help you to integrate those frameworks with Spring.

More on this: Spring allows you to change the similar framework without changing the code. For example...