title: why is ${variable} not substituted
body: <p>I have this little piece of code</p>
  
  <pre><code>&lt;%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %&gt;
  &lt;%@ taglib prefix="fmt" uri="http://java.sun.com/jstl/fmt" %&gt;
  &lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
      &lt;title&gt;&lt;%= request.getAttribute("index_title") %&gt;&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;c:out value="${request['index_title']}" /&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>the expression <code>&lt;%= request.getAttribute("index_title") %&gt;</code> is correctly substituted, but <code>&lt;c:out value="${request['index_title']}" /&gt;</code> is not. I also tried <code>${request['index_title']}</code> and <code>${index_title}</code> but no one works.</p>
  
  <p>That's my first jsp, so I really think it must be a trivial error, but I am not able to understand where the error is.</p>
  
  <p><strong>Additional question:</strong></p>
  
  <p>in my servlet I do <code>request.setAttribute ("index_title", "page title");</code> . Can the problem be related to the fact that what I'm adding to the request is not a bean?</p>