s in the returned set are not
 reflected in the <code>ServletRegistration</code> object, and vice-versa.
 </p></div>
<dl>
<dt><span class="paramLabel">Parameters:</span></dt>
<dd><code>urlPatterns</code> - the URL patterns of the servlet mapping</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the (possibly empty) Set of URL patterns that are already mapped to a different Servlet</dd>
<dt><span class="throwsLabel">Throws:</span></dt>
<dd><code><a href="https://docs.oracle.com/javase/8/docs/api/ja