Automatically enforce code coverage in a Maven project with JaCoCo

May 07, 2025

Put this in your POM file

<properties>
  <!-- 0.90 = 90% minimum coverage -->
  <jacoco-maven-plugin.minimum-coverage>0.90</jacoco-maven-plugin.minimum-coverage>
</properties>

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <executions>
    <execution>
      <id>set-artifact-path-properties</id>
      <goals>
        <goal>properties</goal>
      </goals>
      <phase>initialize</phase>
    </execution>
  </executions>
</plugin>
<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-surefire-plugin</artifactId>
  <configuration>
    <argLine>@{argLine}
      -javaagent:${settings.localRepository}/org/mockito/mockito-core/${mockito.version}/mockito-core-${mockito.version}.jar
      -Xshare:off</argLine>
  </configuration>
</plugin>
<plugin>
  <groupId>org.jacoco</groupId>
  <artifactId>jacoco-maven-plugin</artifactId>
  <version>${jacoco-maven-plugin.version}</version>
  <executions>
    <execution>
      <goals>
        <goal>prepare-agent</goal>
      </goals>
    </execution>
    <execution>
      <id>report</id>
      <goals>
        <goal>report</goal>
      </goals>
      <phase>test</phase>
    </execution>
    <execution>
      <id>jacoco-check</id>
      <goals>
        <goal>check</goal>
      </goals>
      <phase>test</phase>
      <configuration>
        <rules>
          <rule>
            <element>PACKAGE</element>
            <limits>
              <limit>
                <counter>LINE</counter>
                <value>COVEREDRATIO</value>
                <minimum>${jacoco-maven-plugin.minimum-coverage}</minimum>
              </limit>
            </limits>
          </rule>
        </rules>
      </configuration>
    </execution>
  </executions>
</plugin>

The maven-dependency-plugin & maven-surefire-plugin bits aren't strictly related to adding code coverage, but it shows how to update the argLine properly. In my example, I'm adding some extra config to ensure Mockito work with later versions of Java in addition to the code coverage config. You need to include @{argLine} at the beginning to preserve whatever was added when the jacoco-maven-plugin:prepare-agent goal runs.