title: How to configure multi-module Maven + Sonar + JaCoCo to give merged coverage report?
body: <p>I've searched up and down the internet for this one. There's lots of half-answers out there, to do with Maven properties such as <code>${sonar.jacoco.reportPath}</code>, or <code>org.jacoco:jacoco-maven-plugin:prepare-agent</code> or setting <code>maven-surefire-plugin</code> <code>argLine</code> with <code>-javaagent</code>.</p>
  
  <p>Some how, none of these answers, either on their own, or in combination, are producing what I'm after:
  A coverage report which shows a class as covered if it is used in tests higher up the stack, such as entities being used by DAOs, even though it was not fully covered by tests in its own module.</p>
  
  <p>Is there a definitive config somewhere, to achieve this, please?</p>