</dt>
<dd><code>messageInfo</code> - A contextual Object that encapsulates the client request and server response objects.</dd>
<dt>Returns:</dt>
<dd>The authentication context identifier corresponding to the encapsulated request and response objects, or
 null.</dd>
<dt>Throws:</dt>
<dd><code><a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/IllegalArgumentException.html" title="class or interface in java.lang" class="external-link">IllegalArgumentException</a></code> - If the 