We had a similar issue – our head developer found a solution that works for us.
We added this dependency to a couple of our pom.xml files
For those that care, the unit tests in Sonar that were failing were apparently failing because Cobatura by default pulls in an old version of xerces. The version it pulls in is incompatible with JAX-B in Java 8. The library is not used in production code – just Cobatura. Therefore, the fix was to add a test dependency on a more recent version of xerces (2.11.0). This is done by adding the dependency to the pom file:
<dependency>
<groupId>xerces</groupId>
<artifactId>xercesImpl</artifactId>
<version>2.11.0</version>
<scope>test</scope>
</dependency>