Configuring SSL Security

An servlet that requires https can say so in the web.xml file

<security-constraint>
<!-- .... --->
  <user-data-constraint>
    <transport-guarantee>
      CONFIDENTIAL
    </transport-guarantee>
  </user-data-constraint>
</security-constraint>

The servlet can determine if it was called under https with
```
public boolean ServletRequest.isSecure();
```