Jacoco Maven multi module project coverage

Question

Seems like there are couple of questions, which are quite old and things changed from Java 8 support of Jacoco.

My Project contains following structure

Answer 1

Follow below-mentioned instructions

1. Create a new sub-project. This will be used as , report aggregator. parent pom will be like:

<modules>
        <module>A</module>
        <module>B</module>
        <module>C</module>
        <module>ReportAggregator</module>
    </modules>

2. In aggregator branch pom- add other subprojects dependencies.

<dependency>
            <groupId>xyz</groupId>
            <artifactId>A</artifactId>
            <version>${project.version}</version>
        </dependency>

3. In aggregator branch pom- configure jacoco plugin

<plugin>
                <groupId>org.jacoco</groupId>
                <artifactId>jacoco-maven-plugin</artifactId>
                <version>0.8.6</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>prepare-agent</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>report-aggregate</id>
                        <phase>verify</phase>
                        <goals>
                            <goal>report-aggregate</goal>
                        </goals>
                        <configuration>
                            <dataFileIncludes>
                                <dataFileInclude>**/jacoco.exec</dataFileInclude>
                            </dataFileIncludes>
                            <outputDirectory>${project.reporting.outputDirectory}/jacoco-aggregate</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

4. In aggregator branch pom- configure surefire plugin as

<plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.0.0-M5</version>
                <configuration>
                    <systemPropertyVariables>
                        <jacoco-agent.destfile>**/jacoco.exec</jacoco-agent.destfile>
                    </systemPropertyVariables>
                </configuration>
            </plugin>

5. (optional step) If anybody face warning/error like: Classes in bundle '*' do no match with execution data. For report generation, the same class files must be used as at runtime.**

Then add below mentioned lines in aggregator branch pom

 <plugin>
                <groupId>org.jacoco</groupId>
                <artifactId>jacoco-maven-plugin</artifactId>
                <version>0.8.6</version>
                <executions>
                    <execution>
                        <id>instrument-ut</id>
                        <goals>
                            <goal>instrument</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>restore-ut</id>
                        <goals>
                            <goal>restore-instrumented-classes</goal>
                        </goals>
                    </execution>
                    <execution>
                        <goals>
                            <goal>prepare-agent</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>report-aggregate</id>
                        <phase>verify</phase>
                        <goals>
                            <goal>report-aggregate</goal>
                        </goals>
                        <configuration>
                            <dataFileIncludes>
                                <dataFileInclude>**/jacoco.exec</dataFileInclude>
                            </dataFileIncludes>
                            <outputDirectory>${project.reporting.outputDirectory}/jacoco-aggregate</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

6. run mvn clean install

Answer 2

One problem in multimodule projects is caused, if the aggregator pom is used as parent pom for the modules either, like it is the case in the above example:

- parentAggregator pom
---sub module A pom.xml -> parentAggregator pom
---sub module B pom.xml -> parentAggregator pom
---sub module C pom.xml -> parentAggregator pom

In this case, the build order is:

- parentAggregator
- sub module A
- sub module B
- sub module C

which means, that the parent aggregator can not collect complete information. In my case a transfer of data into sonarQube by mvn sonar:sonar resulted in unexpected and uncomplete results.

Changing the module structure to:

- aggregator pom
-- parent pom
---sub module A pom.xml -> parent pom
---sub module B pom.xml -> parent pom
---sub module C pom.xml -> parent pom

will change the build order to:

- parent
- sub module A
- sub module B
- sub module C
- aggregator

In this case aggregator will be the last one and work with the results of the modules. In my case the results in SonarQube were like expected.

Answer 3

Copy the code end of article at https://dzone.com/articles/jacoco-maven-multi-module and put it in .... works for me. Just add as many modules as you would like to report on. Also I needed to change antrun from 1.7 to 1.8 for the ant tasks to run.

Answer 4

JaCoCo version 0.7.7 can generate an aggregate coverage report from multiple Maven modules through a new goal jacoco:report-aggregate.

Answer 5

After scannning many solutions I created a simple but complete Jacoco demo project showing:

• Multi module project
• Unit test (via mvn clean install)
• Integration test (via mvn clean install -P integration-test)
• Jacoco - test coverage ( both aggregate datafile and aggregate reporting)
• FindBugs - code quality

Enjoy the simple demo project.