title: What is the purpose of a JSESSIONID suffix?
body: <p>After using a browser to authenticate into my service, I find a cookie set with the following key\value pair:</p>
  
  <pre><code>JSESSIONID=40d4b01c47ddb858718291d319a1a817d3037fdc6f2c341c195a94dc6ee8e8a1.e38Lb3qTb3aKai0RbxeMahqNbN90; path=/MyService; secure
  </code></pre>
  
  <p>Note the suffix (i.e. after the '.' : <strong>e34Mc3uLa3yPbO0La3aNa3eTc38Ke0</strong>)</p>
  
  <p>When I use Java servetl's API to get the session id (<code>javax.servlet.http.HttpSession.getId()</code>), I get the following value</p>
  
  <pre><code>40d4b01c47ddb858718291d319a1a817d3037fdc6f2c341c195a94dc6ee8e8a1
  </code></pre>
  
  <p>Which is the same as the first portion of the cookie variable value I just mentioned !</p>
  
  <p>I once tried to maintain a session between multiple HTTP requests on ColdFusion (CF) (Its ok if you don't know what CF is, its simply a platform to develop applications) and I couldn't maintain the session if I set the cookie variable <strong>JSESSIONID</strong> to the whole value I mentioned in the beginning in this question. To maintain the session correctly I had to send the first portion of the session id (i.e. before the '.')</p>
  
  <p>So my question is, why does the servlet API return a part of the JSESSIONID, while the cookie value returned from the server has a suffix ? Where does this suffix com from and what is it's purpose ?</p>