code> if
 authentication is incomplete and the underlying login mechanism has committed, in the response, the message (e.g.,
 challenge) and HTTP status code to be returned to the user.</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/java/io/IOException.html?is-external=true" title="class or interface in java.io">IOException</a></code> - if an input or output error occurred while reading from this request or writing to the given
 response</