Cobertura - Code coverage tool

Cobertura is a Java tool that calculates the percentage of code accessed by tests. It can be used to identify which parts of your Java program are lacking test coverage. it instruments Java bytecode after it has been compiled. Reports are generated in HTML and XML. It shows cyclomatic code complexity of each class, and the average cyclomatic code complexity for each package and for the overall product.

This tool can be executed from Ant or from command line. Appfuse and other popular projects are using this tool. This tool is based on jcoverage.