Our repository has all src code under /src. So when running tests and coverage the coverage.xml file is generated in $WORKSPACE/src. In the job config I specify **/coverage.xml in the location. Th eCobertura plugin finds the coverage report but states:

Source code is unavailable. Some possible reasons are:

This is not the most recent build (to save on disk space, this plugin only keeps the most recent builds source code).
Cobertura found the source code but did not provide enough information to locate the source code.
Cobertura could not find the source code, so this plugin has no hope of finding it.

I believe this is due to the fact that coverage.xml records the relative path to the files. As this file is in $WORKSPACE/src I would expect it to find the files in $WORKSPACE/src/<relative path>, but I susepct it's omitting the 'src' directory.