Clover

http://www.atlassian.com/software/clover/overview

Java and Groovy Code Coverage

Clover provides the metrics you need to better balance the effort between writing code that does stuff and code that tests stuff.

Clover runs in your IDE or your continuous integration system, and includes Test Optimization to make your tests run faster and fail more quickly.

Clover in a Nutshell (1:58)