title: Jcoco does not generate reports when jars are included in report task
body: <p>I am running JUnits on build. Build includes jars of the product. We want to run code coverage on classes in jar. We have unobfuscated jars.
  We have ant script as follows </p>
  
  <pre><code>&lt;target name="codeCoverageReport"&gt;
      &lt;jacoco:report&gt;
      &lt;executiondata&gt;
          &lt;file file="${codecoverage.file}"/&gt;
      &lt;/executiondata&gt;
      &lt;structure name="eQ Adapter And Plug-ins Code Coverage Report "&gt;
      &lt;classfiles&gt;
          &lt;fileset dir="${classes}"&gt;
              &lt;include name="**/*.class" /&gt;
          &lt;/fileset&gt;
          &lt;fileset dir="${pluginJars}"&gt;
              &lt;include name="*.jar" /&gt;
          &lt;/fileset&gt;
      &lt;/classfiles&gt;
      &lt;sourcefiles encoding="UTF-8"&gt;
          &lt;fileset dir="${sourceDrive}/src"/&gt;
      &lt;/sourcefiles&gt;
      &lt;/structure&gt;
      &lt;html destdir="${codecoverage.reports}"/&gt;
      &lt;csv destfile="${codecoverage.reports}/report.csv"/&gt;
      &lt;xml destfile="${codecoverage.reports}/report.xml"/&gt;
      &lt;/jacoco:report&gt;
  &lt;/target&gt;
  
  
  
      &lt;jacoco:coverage enabled="true" destfile="${codecoverage.file}" append="true" includes="**/*.class" &gt;
          &lt;junit printsummary="yes" failureproperty="junit.failed" haltonfailure="no" fork="true" forkmode="once" maxmemory="2048m"&gt;
              &lt;classpath refid="test.classpath" /&gt;
              &lt;formatter type="xml"  /&gt;
              &lt;batchtest todir="${reports.dir}/tmp"&gt;
                  &lt;fileset dir="${src}"&gt;
                      &lt;include name="**/${testFileSet}" /&gt;
                  &lt;/fileset&gt;
              &lt;/batchtest&gt;
          &lt;/junit&gt; 
      &lt;/jacoco:coverage&gt;
  </code></pre>
  
  <p>We have also tried </p>
  
  <pre><code>&lt;target name="codeCoverageReport"&gt;
          &lt;jacoco:report&gt;
          &lt;executiondata&gt;
              &lt;file file="${codecoverage.file}"/&gt;
          &lt;/executiondata&gt;
          &lt;structure name="eQ Adapter And Plug-ins Code Coverage Report "&gt;
          &lt;classfiles&gt;
              &lt;fileset dir="${classes}"&gt;
                  &lt;include name="**/*.class" /&gt;
              &lt;/fileset&gt;
          &lt;/classfiles&gt;
          &lt;sourcefiles encoding="UTF-8"&gt;
              &lt;fileset dir="${sourceDrive}/src"/&gt;
              &lt;fileset dir="${pluginJars}"&gt;
                  &lt;include name="*.jar" /&gt;
              &lt;/fileset&gt;
          &lt;/sourcefiles&gt;
          &lt;/structure&gt;
          &lt;html destdir="${codecoverage.reports}"/&gt;
          &lt;csv destfile="${codecoverage.reports}/report.csv"/&gt;
          &lt;xml destfile="${codecoverage.reports}/report.xml"/&gt;
          &lt;/jacoco:report&gt;
      &lt;/target&gt;
  </code></pre>
  
  <p>But Ant shows following error </p>
  
  <p><strong><em>Error while creating report</em></strong></p>
  
  <p>Without Jar path it works fine. But It does not include classes from jars in reports.</p>
  
  <p>Any possible solution for this ?</p>