Merging test coverage and test results from multiple Jenkins jobs

Faced similar issue, tweaked jacoco maven plugin config to merge jacoco results. Basically merged jacoco-unit.exec and jacoco-it.exec into one binary and published that merged result on Jenkins via pipeline step.

pom.xml:

            <plugin>                    <inherited>false</inherited>                    <groupId>org.jacoco</groupId>                    <artifactId>jacoco-maven-plugin</artifactId>                    <version>${jacoco.agent.version}</version>                    <executions>                        <execution>                            <id>merge-results</id>                            <phase>post-integration-test</phase>                            <goals>                                <goal>merge</goal>                            </goals>                            <configuration>                                <fileSets>                                    <fileSet>                                        <directory>${project.parent.build.directory}</directory>                                        <includes>                                            <include>jacoco-*.exec</include>                                        </includes>                                    </fileSet>                                </fileSets>                                <destFile>${project.parent.build.directory}/jacoco.exec</destFile>                            </configuration>                        </execution>                    </executions>                </plugin>

Jenkinsfile:

            echo 'Publish Jacoco trend'            step($class: 'JacocoPublisher',                    execPattern: '**/jacoco.exec',                    classPattern: '**/classes',                    sourcePattern: '**/src/main/java',            )

However you still have to fetch jacoco binaries from several Jenkins builds by another build step or specify their locations explicitly.