Have you ever tried it with one of the automated tools? I use Pitest extensively to mutate my Java code bases and found it is not too much slower then regular line and branch code coverage tools when you use a history file so only diffs are needed. The trade off of a few more seconds of build time is worth the benefit of the coverage report and being able to fail the build if coverage drops too low for me.

http://pitest.org/quickstart/maven/