title: How to add request parameter in jsf2?
body: <p>In my app, before upgrading to jsf 2, when doing a custom redirect I used to manually put a request parameter with a specific value in external context like this:</p>
  
  <pre><code>FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap()
                  .put(CmwNavigationControllerBean.PARAM_DISPLAY_TARGET_POPUP, "true");
  </code></pre>
  
  <p>Now this line, throws an exception because it seems that this map is no longer allowed to be modified:</p>
  
  <pre><code>at java.util.Collections$UnmodifiableMap.put(Unknown Source) [rt.jar:1.7.0]
  </code></pre>
  
  <p>Isn't really no other way to bypass this exception? I'm doing refactoring because of upgrade and I try to keep the changes at minimal level.</p>