...

If you're having problems when upgrading from an older version of Surefire to a newer version, try setting useSystemClassLoader=false to see if that helps. You can do that with the POM snippet below, or by setting "-Dsurefire.useSystemClassLoader=false".

<project>
  [...]
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <useSystemClassLoader>false</useSystemClassLoader>
        </configuration>
      </plugin>
    </plugins>
  </build>
  [...]
</project>

Debugging Classpath Problems

...

• Run mvn with --debug (aka -X) to get more detailed output
• Check your forkMode. If forkMode=never, it's impossible to use the system classloader; we have to use an isolated classloader.
• If useSystemClassLoader=true, look at the surefire booter jar. Open it up (it's just a zip) and read its manifest.
• Run mvn with -Dmaven.surefire.debug, and attach to the running process with a debugger.