The coverage stuff I have done for ofbiz is based on the method I did it for webslinger. I wrote a shim to allow for other coverage tools to be used, then wrote a classpath/jar walker to find all classes matching a particular pattern, a dynamic temporary classloader to load the instrumenter, then a concrete implementation that uses Cobertura.
I can check everything in, including a build.xml tweak, but can't add the cobertura library itself. So, with that out of the way, here's my current headache. cobertura-1.9.1 does not handle annotation definitions(@interface) in java files. 1.9.3 does. However, that requires upgrading from asm-2.2.3 to asm-3.2. But then groovy fails, 1.6.0-1.6.7 still use asm-2.2.3. Groovy has to be upgraded to 1.7-rc-2. But then webslinger fails, 'cuz it has direct links to asm, cobertura, and groovy. I've done the webslinger side, and my test cases pass, still have to upgrade the ofbiz stuff. ps: I love java :|