Book excerpt: Discover the Jakarta EE Contexts and Dependency Injection (CDI 2.0) framework which helps you write better code through the use of well-defined enterprise Java-based components and beans (EJBs). If you have ever wanted to write clean Java EE code, this short book is your best guide for doing so: you will pick up valuable tips along the way from your author's years of experience teaching and coding. Introducing Jakarta EE CDI covers CDI 2.0 in detail and equips you with the theoretical underpinnings of Java EE, now Jakarta EE. This book is packed with so much that by the end of it, you will feel confident to use your new-found knowledge to help you write better, readable, maintainable, and long-lived mission-critical software. What You Will Learn Write better code with the Jakarta EE Contexts and Dependency Injection (CDI) framework Work with the powerful, extensible, and well-defined contextual life cycle for components Use CDI’s mechanism for decoupling application components through a typesafe event API Build typesafe interceptors for altering the behaviour of components at runtime Harness the well-defined qualifier system for easy isolation of beans Convert almost any valid Java type to a CDI managed bean with CDI’s producer mechanism Who This Book Is For Experienced enterprise Java, Java EE, or J2EE developers who may be new to CDI or dependency injection.