Today we hit a stack trace as we pushed a project from Hudson to SonarQube. It complained about a problem injecting the CoberturaReportMojo. We were using the latest version (2.6) of the Cobertura Maven Plugin and encountered no problems, when creating a cobertura report within our Maven site.
This article shows a solution to workaround this problem.
The Problem
We were able to reproduce the issue by calling
mvn cobertura:cobertura
The full stack trace is:
[INFO] <<< cobertura-maven-plugin:2.6:cobertura (default-cli) @ cobertura-test <<<
[INFO]
[INFO] --- cobertura-maven-plugin:2.6:cobertura (default-cli) @ cobertura-test ---
org.sonatype.guice.bean.reflect.Logs$JULSink warn
WARNUNG: Error injecting: org.codehaus.mojo.cobertura.CoberturaReportMojo
java.lang.TypeNotPresentException: Type org.codehaus.mojo.cobertura.CoberturaReportMojo not present
at org.sonatype.guice.bean.reflect.URLClassSpace.loadClass(URLClassSpace.java:109)
at org.sonatype.guice.bean.reflect.NamedClass.load(NamedClass.java:45)
at org.sonatype.guice.bean.reflect.AbstractDeferredClass.get(AbstractDeferredClass.java:45)
at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:84)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.provision(InternalFactoryToInitializableAdapter.java:52)
at com.google.inject.internal.ProviderInternalFactory$1.call(ProviderInternalFactory.java:70)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:100)
at org.sonatype.guice.plexus.lifecycles.PlexusLifecycleManager.onProvision(PlexusLifecycleManager.java:138)
at com.google.inject.internal.ProvisionListenerStackCallback$Provision.provision(ProvisionListenerStackCallback.java:108)
at com.google.inject.internal.ProvisionListenerStackCallback.provision(ProvisionListenerStackCallback.java:55)
at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:68)
at com.google.inject.internal.InternalFactoryToInitializableAdapter.get(InternalFactoryToInitializableAdapter.java:45)
at com.google.inject.internal.InjectorImpl$3$1.call(InjectorImpl.java:965)
at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1011)
at com.google.inject.internal.InjectorImpl$3.get(InjectorImpl.java:961)
at com.google.inject.Scopes$1$1.get(Scopes.java:59)
at org.sonatype.guice.bean.locators.LazyBeanEntry.getValue(LazyBeanEntry.java:83)
at org.sonatype.guice.plexus.locators.LazyPlexusBean.getValue(LazyPlexusBean.java:49)
at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:253)
at org.codehaus.plexus.DefaultPlexusContainer.lookup(DefaultPlexusContainer.java:245)
at org.apache.maven.plugin.internal.DefaultMavenPluginManager.getConfiguredMojo(DefaultMavenPluginManager.java:455)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:92)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: java.lang.NoClassDefFoundError: org/apache/maven/reporting/MavenReport
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:386)
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClassFromSelf(ClassRealm.java:386)
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:42)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
at org.sonatype.guice.bean.reflect.URLClassSpace.loadClass(URLClassSpace.java:101)
... 41 more
Caused by: java.lang.ClassNotFoundException: org.apache.maven.reporting.MavenReport
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
... 68 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
Looking at the dependencies of the Cobertura Maven Plugin it was obvious that the referenced class org.apache.maven.reporting.MavenReport is part of this artifact:
<dependency> <groupId>org.apache.maven.reporting</groupId> <artifactId>maven-reporting-api</artifactId> <version>2.0.8</version> </dependency>
So we tried to replace the artifact by a newer version. The next micro release already fixed the issue.
The Solution
So here is the fix for the configuration of the cobertura plugin:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>cobertura-maven-plugin</artifactId>
<version>2.6</version>
<dependencies>
<dependency>
<groupId>org.apache.maven.reporting</groupId>
<artifactId>maven-reporting-api</artifactId>
<version>2.0.9</version>
</dependency>
</dependencies>
</plugin>
Conclusion
The solution was not that obvious to us from the start. Searching the internet slowly revealed the root cause of the issue.
This information here may help anyone to save time looking for a solution. 
