Multi Module Maven Project Code Coverage Issue on Sonar - maven

Question

I have a question related to multi module maven project with JaCoCo and SONAR.
I have a parent and 3 child modules.
parent |-child1 - pom.xml |-child2 - pom.xml |-child3 - pom.xml |-pom.xml
I include the JaCoCo plugin in the parent pom.xml. When I run the mvn clean install sonar:sonar build from parent pom.xml, I see that each child generates its own jacoco.exec file. Something like this child1/target/jacoco.exec, child2/target/jacoco.exec etc . However, there is no jacoco.exec been generated in the parent level.
When I run my sonar analysis, I see that the unit test coverage is showing up as 0.0% on the sonar dashboard.
My question is
1. What should I do to see the unit test coverage for the entire project?
2. To show the one unit test coverage, Does SONAR pick the jacoco.exec file from the parent level or from the child level?
Please help. This is really a road blocker for me. Appreciate all your inputs.

Answer 1

I was facing the same issue, then I included the following in each module pom xml and it worked:
<!-- Sonar START -->
<sonar.java.coveragePlugin>jacoco</sonar.java.coveragePlugin>
<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
<sonar.jacoco.reportPath>${project.basedir}/../target/jacoco.exec</sonar.jacoco.reportPath>
<sonar.language>java</sonar.language>
<jacoco.version>0.7.9</jacoco.version>
<!-- Sonar START -->
Plugins :
<!-- SONAR config START -->
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>${jacoco.version}</version>
<configuration>
<destFile>${sonar.jacoco.reportPath}</destFile>
<append>true</append>
</configuration>
<executions>
<execution>
<id>agent</id>
<goals>
<goal>prepare-agent</goal>
</goals>
<configuration>
<tasks>
<echo>Project Base Path (WEB):: ${project.basedir}</echo>
<echo>Jacoco exec target path (WEB):: ${sonar.jacoco.reportPath}</echo>
</tasks>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.sonarsource.scanner.maven</groupId>
<artifactId>sonar-maven-plugin</artifactId>
<version>3.2</version>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>sonar-maven-plugin</artifactId>
<version>2.7</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19</version>
<configuration>
<argLine>${argLine}</argLine>
</configuration>
</plugin>
<!-- SONAR config END -->
And configure in Jenkins for "Goals and options" as:
sonar:sonar
For Running specific tests :
sonar:sonar -DfailIfNoTests=false -Dtest=<Test Class> test

Answer 2

I had the similar issue, 0.0% coverage & no unit tests count on Sonar dashboard with SonarQube 6.7.2:
Maven : 3.5.2,
Java : 1.8,
Jacoco : Worked with 7.0/7.9/8.0,
OS : Windows
After a lot of struggle finding for correct solution, resolved issue with this configuration my parent pom looks like:
<properties>
<!--Sonar -->
<sonar.java.coveragePlugin>jacoco</sonar.java.coveragePlugin>
<sonar.dynamicAnalysis>reuseReports</sonar.dynamicAnalysis>
<sonar.jacoco.reportPath>${project.basedir}/../target/jacoco.exec</sonar.jacoco.reportPath>
<sonar.language>java</sonar.language>
</properties>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
<plugin>
<groupId>org.sonarsource.scanner.maven</groupId>
<artifactId>sonar-maven-plugin</artifactId>
<version>3.4.0.905</version>
</plugin>
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.7.9</version>
<configuration>
<destFile>${sonar.jacoco.reportPath}</destFile>
<append>true</append>
</configuration>
<executions>
<execution>
<id>agent</id>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</pluginManagement>
</build>
I've tried few other options like jacoco-aggregate & even creating a sub-module by including that in parent pom but nothing really worked & this is simple. I see in logs <sonar.jacoco.reportPath> is deprecated,but still works as is and seems like auto replaced on execution or can be manually updated to <sonar.jacoco.reportPaths> or latest. Once after doing setup in cmd start with mvn clean install then mvn org.jacoco:jacoco-maven-plugin:prepare-agent install & then do mvn sonar:sonar , this is what I've tried please let me know if some other best possible solution available.Hope this helps!! If not please post your question..