title: Append the value of argLine param in maven-surefire-plugin
body: <p>I am using <code>maven-surefire-plugin</code> + <code>Sonar</code> together and I would like to add some extra value to <code>argLine</code> parameter of the maven-surefire-plugin.</p>
  
  <p>So I did it:</p>
  
  <pre><code>&lt;build&gt;
      &lt;plugins&gt;
          &lt;plugin&gt;
              &lt;groupId&gt;org.apache.maven.plugins&lt;/groupId&gt;
              &lt;artifactId&gt;maven-surefire-plugin&lt;/artifactId&gt;
              &lt;version&gt;2.20.1&lt;/version&gt;
              &lt;configuration&gt;
                  &lt;argLine&gt;-DCRR.Webservice.isSimulated=true -D...&lt;/argLine&gt;
              &lt;/configuration&gt;
          &lt;/plugin&gt;
          ...
      &lt;/plugins&gt;
  &lt;/build&gt;
  </code></pre>
  
  <p>But in this case I am overwriting the original value of the <code>argLine</code> parameter and Sonar does not generate jacoco.exec file.</p>
  
  <p>I can see in the maven debug log (-X) that the value of argLine param without overwriting its value is <code>-javaagent:/opt/jenkins/.../myproject-SONAR/.repository/org/jacoco/org.jacoco.agent/0.7.4.201502262128/org.jacoco.agent-0.7.4.201502262128-runtime.jar=destfile=/opt/jenkins/.../myproject-SONAR/target/jacoco.exec</code>.</p>
  
  <p>What is the proper way to APPEND the original value of this parameter (keep the original + add extra values)?</p>
  
  <p>I am using Apache Maven 3.5.0, Java version: 1.8.0_131, vendor: Oracle Corporation.</p>