Ever wondered how web servers like Tomcat process requests, or what really happens behind frameworks such as Spring? This book takes you beneath the surface of Java web development to uncover the why behind the tools you use every day. Rather than focusing solely on coding recipes, this book emphasizes the underlying concepts and design principles that govern how web servers and frameworks operate. Starting with low-level socket programming, you’ll build a multithreaded HTTP server from the ground up and extend it into a lightweight application server capable of handling dynamic content. Along the way, you’ll master HTTP request parsing, response generation, servlet-like request handling, and Java reflection and annotations for metaprogramming. As you progress, you’ll evolve this infrastructure into your own Java framework with embedded Tomcat, annotation-driven routing, object serialization with Jackson, and basic dependency injection modeled on Jakarta CDI. By the end of this journey, you’ll understand the principles behind them, enabling you to reason about system design, troubleshoot complex issues, and apply these concepts across frameworks and programming languages. *Email sign-up and proof of purchase required