e empty string is returned. If the message header is present more than once
 then the values of joined together and separated by a ',' character.</dd>
<dt>See Also:</dt>
<dd>
<ul class="tag-list">
<li><a href="#getHeaders()"><code>getHeaders()</code></a></li>
<li><a href="#getStringHeaders()"><code>getStringHeaders()</code></a></li>
</ul>
</dd>
</dl>
</section>
</li>
<li>
<section class="detail" id="containsHeaderString(java.lang.String,java.lang.String,java.util.function.Predicate)">
<h3>containsHeaderStri