Jacoco: Aggregating branch coverage report of multiple test case method - junit

Question

I am using Ant JUnit.
<for list="${test.classes.list}" param="class" delimiter=",">
<sequential>
<for list="${#{class}}" param="method" delimiter=",">
<sequential>
<jacoco:coverage destfile="${basedir}/jacoco.exec">
<junit fork="true">
......
<test name="#{class}" methods="#{method}"/>
</junit>
</jacoco:coverage>
<jacoco:report>
......
<csv destfile="coverage/#{class}.#{method}/report.csv"/>
</jacoco:report>
</sequential>
</for>
</sequential>
In the property file, I have:
test.classes.list=a.b.C,d.e.F
a.b.C=test1,test2
d.e.F=test1,test2,test3
Jacoco will produce a report for each test case method.
The problem is branch coverage for each class is not accurate as covered branches may be overlapped.
How do I aggregate the reports to get a correct branch coverage for whole project?

Answer 1

JaCoCo comes with Ant tasks to launch Java programs with execution recording and for creating coverage reports from the recorded data. Execution data can be collected and managed with the tasks coverage, agent, dump and merge.
This is an example from their Web page of how to merge a set of *.exec files:
<jacoco:merge destfile="merged.exec">
<fileset dir="executionData" includes="*.exec"/>
</jacoco:merge>