Find unused code in Java webapp

I have a Tomcat-powered webapp that builds to a war and is deployed. It's been used for a few somewhat different tasks over the years, and it has lots and lots and lots of classes and libraries.

I'd like to do some sort of autom开发者_JAVA技巧ated census of used and unused classes (and maybe even dependencies) and get a report back for which classes, methods, or even lines that have not been executed over a few days of production use.

Is there a tool that could generate such a report for me?

You're looking for a code coverage tool.

For Java, try EMMA:

http://emma.sourceforge.net/

If you are talking about statistics of unused code (functionally) in production system you can start with simply enabling the "-verbose:class" as startup parameter. I don't think Sun JDK (at least JDK 5)supports regular expression to restrict the log to specific package(s).

It's better to analyze the unused method/block using static analysis tools like PMD/Sonar rather than instrumenting to method/line level.