Jacoco generate code coverage reports.

root-pom.xml

<project>
    [...]
    <build>
        <plugins>
            <plugin>
                <groupId>org.jacoco</groupId>
                <artifactId>jacoco-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <id>prepare-agent</id>
                        <goals>
                            <goal>prepare-agent</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>report-aggregate</id>
                        <phase>test</phase>
                        <goals>
                            <goal>report-aggregate</goal><!-- other modules -->
                            <goal>report</goal><!-- this modules -->
                        </goals>
                    </execution>
                </executions>
            </plugin>
        <plugins>
    </build>
    [...]
    <pluginManagement>
        <plugins>
            <!--	unit test plugin		-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.0.0-M5</version>
                <dependencies>
                    <dependency>
                        <groupId>org.apache.maven.surefire</groupId>
                        <artifactId>surefire-junit47</artifactId>
                        <version>3.0.0-M5</version>
                    </dependency>
                </dependencies>
                <configuration>
                    <!-- for jacoco -->
                    <!--suppress UnresolvedMavenProperty -->
                    <argLine>${argLine} -Dfile.encoding=UTF-8</argLine> 
                    <forkCount>1</forkCount>
                    <reuseForks>false</reuseForks>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
    [...]
</project>

sub-module-pom.xml

<project>
[...]
<plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
            <includes>
                <include>[path]</include>
            </includes>
        </configuration>
    </plugin>
</plugins>
[...]
</project>