title: Strange Behaiour with Camel + Groovy + Spring DSL
body: <p>I have the following route:</p>
  
  <pre><code>    &lt;camel:camelContext  id="convert"&gt;
              &lt;camel:route&gt;
              &lt;camel:from uri="restlet:/convert/{id}"/&gt;
              &lt;camel:transform&gt;
                  &lt;camel:groovy&gt;
                      request.headers.id
                  &lt;/camel:groovy&gt;
               &lt;/camel:transform&gt;
          &lt;/camel:route&gt;
      &lt;/camel:camelContext&gt;
  </code></pre>
  
  <p>This route should simply return the value passed in the URL as id parameter. 
  When I execute this, the first call works. Anything after the first call returns the value passed in the first call. So, if first call is hostname/convert/999, any other call will return 999 no matter what id is passed in the URL. It looks like groovy is doing some stateful thing that I don't understand.</p>
  
  <p>Any thoughts?</p>
  
  <p>The same thing seems to happen with JavaScript.</p>
  
  <pre><code>  &lt;camel:camelContext  id="convert"&gt;
           &lt;camel:route&gt;
              &lt;camel:from uri="restlet:/convert/{id}"/&gt;
               &lt;camel:transform&gt;
                  &lt;camel:javaScript&gt;request.headers.get('id')&lt;/camel:javaScript&gt;
               &lt;/camel:transform&gt;
          &lt;/camel:route&gt;
    &lt;/camel:camelContext&gt;
  </code></pre>