ception.html?is-external=true" title="class or interface in java.lang">IllegalStateException</a></code> - if <a href="../../../jakarta/servlet/http/HttpServletRequest.html#isTrailerFieldsReady--"><code>isTrailerFieldsReady()</code></a> is false</dd>
<dt><span class="simpleTagLabel">Since:</span></dt>
<dd>Servlet 4.0</dd>
<dt><span class="simpleTagLabel">Implementation Specification:</span></dt>
<dd>The default implementation returns an empty map.</dd>
</dl>
</li>
</ul>
<a name="isTrailerFieldsReady--">
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