What are the differences between black box testing and white box testing?

When responding to a question about the differences between black hat and white hat testing, start by defining each of these methodologies. Then follow up by contrasting and comparing the two. You may want to finish your answer by describing how you have used this in your previous software development efforts. Providing an example will strengthen your answer.

"Black box and white box testing are both ethical hacking practices used to determine the vulnerability of a software product. White box testing tests an application with the hacker understanding its structure and code. This type of testing is typically performed by the programmer who wrote the code and is conducted as unit tests. Black-box testing tests an application without knowing its code or structure. Testers focus on the software functionality rather than the code or data."