I solved this issue by using cobertura-it plugin. It extends the original cobertura plugin and allows to use report-only goal. In addition, I must run two separate commands (see below) to test and generate reports (merging to 1 command does not work). Here is my plugin configuration.
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>cobertura-it-maven-plugin</artifactId>
<version>2.5</version>
<configuration>
<formats>
<format>html</format>
</formats>
<check>
<haltOnFailure>false</haltOnFailure>
</check>
</configuration>
<executions>
<execution>
<id>pre-integration-test</id>
<phase>pre-integration-test</phase>
<goals>
<goal>cobertura</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>7.4.2.v20110526</version>
<configuration>
<stopKey>aaaaaaaaaaaaa</stopKey>
<stopPort>8085</stopPort>
</configuration>
<executions>
<execution>
<id>start-jetty</id>
<phase>pre-integration-test</phase>
<goals>
<goal>run</goal>
</goals>
<configuration>
<scanIntervalSeconds>0</scanIntervalSeconds>
<daemon>true</daemon>
<classesDirectory>target/generated-classes/cobertura</classesDirectory>
</configuration>
</execution>
<execution>
<id>stop-jetty</id>
<phase>post-integration-test</phase>
<goals>
<goal>stop</goal>
</goals>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>net.sourceforge.cobertura</groupId>
<artifactId>cobertura</artifactId>
<version>1.9.4.1</version>
</dependency>
</dependencies>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<version>2.10</version>
<executions>
<execution>
<id>integration-test</id>
<phase>integration-test</phase>
<goals>
<goal>integration-test</goal>
</goals>
</execution>
<execution>
<id>verify</id>
<phase>verify</phase>
<goals>
<goal>verify</goal>
</goals>
</execution>
</executions>
</plugin>
So I run this:
mvn clean verify
Note that after Jetty is stopped, there is some cobertura messages:
[INFO] -------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] -------------------------------------------------------
[INFO] Total time: 1 minute 13 seconds
[INFO] Finished at: Sun Nov 13 12:58:29 ICT 2011
[INFO] Final Memory: 86M/204M
[INFO] -------------------------------------------------------
2011-11-13 12:58:29.765:WARN::4 threads could not be stopped
Flushing results...
Flushing results done
Cobertura: Loaded information on 342 classes.
Cobertura: Saved information on 342 classes.
Finally, I use mvn site to generate reports. Here is my report configuration
<reporting>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-report-plugin</artifactId>
<!-- An error on version 2.8 -->
<version>2.7</version>
<configuration>
<reportsDirectories>
<reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
<reportsDirectory>${project.build.directory}/failsafe-reports</reportsDirectory>
</reportsDirectories>
</configuration>
<reportSets>
<reportSet>
<reports>
<report>report-only</report>
</reports>
</reportSet>
</reportSets>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-project-info-reports-plugin</artifactId>
<version>2.1</version>
<configuration>
<!-- An error that takes long time to generate this report -->
<dependencyLocationsEnabled>false</dependencyLocationsEnabled>
</configuration>
<reportSets>
<reportSet>
<reports>
<report>dependencies</report>
</reports>
</reportSet>
</reportSets>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>cobertura-it-maven-plugin</artifactId>
<configuration>
<formats>
<format>html</format>
<format>xml</format>
</formats>
</configuration>
<reportSets>
<reportSet>
<reports>
<report>report-only</report>
</reports>
</reportSet>
</reportSets>
</plugin>
</plugins>
</reporting>
