JaCoCo – the new and revolting Java Code Coverage tool
I’ve stumpled across JaCoCo while searching for a possibility to have the code coverage of a multi modul project merged.
JaCoCo is made from the same developer, which made the eclipse plugin EclEmma.
The big advantage (and disadvantage maybe) is that JaCoCo uses a JavaAgent to instrument the classes on the fly. That means no extra instrumentation step is needed beforehand. The disadvantage is, you need to specify the JavaAgant as a JVM parameter.
But imho it’s a far better solution of the instrumentation problem as the old instrument the classes you want coverage for step.
JaCoCo is available for Sonar 2.2. Sadly there doesn’t exist a stable maven2 plugin yet (there is one for sonar and on mojo/sandbox). But it should only be a matter of time 
http://www.eclemma.org/jacoco/
