Foi publicado no portal Java.net um excelente tutorial sobre Reflection:
[quote]Have you ever wondered how an IDE lists all your class details, including the private fields and methods? Or how IDEs are also able to list the classes (together with their details) archived within JAR files that include no source?
These are examples of reflection.
Together with listing the contents of an arbitrary class, this article will illustrate how reflection can be used to leverage programming and push it to a higher level of abstraction. We will start from very basic examples and move forth by applying reflection within a simple application.[/quote]
Confira em: http://today.java.net/pub/a/today/2008/02/12/reflection-in-action.html