Chapter 4. Persistence Fundamentals

Objects contain the possibility of all situations.

—Ludwig Wittgenstein, Tractatus Logico Philosphicus

Persistence grants immortality to your business applications. Without it, you lose all of your application data every time the server shuts down. Database programming is the development of persistence mechanisms to save an application's state to a relational database. In this book, I will cover a variety of persistence mechanisms, but this chapter introduces the basics through a custom guest book JSP application.