title: How to add a parameter to the existing HttpServletRequest of my Java Servlet?
body: <p>I want to add a new parameter to the parameter map of my <code>HttpServletRequest</code>.</p>
  
  <p>The following code</p>
  
  <pre><code> request().getParameterMap().put("j_username", user);
   request().getParameterMap().put("j_password", pwd);
  </code></pre>
  
  <p>creates this error</p>
  
  <pre><code>no modifications are allowed to a locked parameter map
  </code></pre>
  
  <p>What is the correct way to do this?</p>