What is reflection and why is it useful?

Question

What is reflection, and why is it useful?

I\'m particularly interested in Java, but I assume the principles are the same in any language.

Answer 1

Reflection has many uses. The one I am more familiar with, is to be able to create code on the fly.

IE: dynamic classes, functions, constructors - based on any data (xml/array/sql results/hardcoded/etc..)