title: Having a map as a Maven plugin parameter
body: <p>I am using maven 3 and I want to pass in a type Map as a parameter.</p>
  
  <p>I have this in my mojo at the moment:</p>
  
  <pre><code>/**
   * @parameter expression="${rep.env}" alias="environments"
   * @required
   */
  private Map&lt;String,String[]&gt; environments = null;
  </code></pre>
  
  <p>I am passing in this during the configuration:</p>
  
  <pre><code>                &lt;environments&gt;
                      &lt;Testing&gt;
                          &lt;param&gt;
                              unit
                          &lt;/param&gt;
                      &lt;/Testing&gt;
                  &lt;/environments&gt;
  </code></pre>
  
  <p>It is complaining that it is missing the parameter environments, are you allowed to do this in maven?</p>