"block">This method is called with the endpoint configuration object of the endpoint this encoder is intended for when it
 is about to be brought into service.</div>
</div>
<div class="col-first even-row-color"><code>abstract void</code></div>
<div class="col-second even-row-color"><span class="type-name-label">Endpoint.</span><code><a href="../Endpoint.html#onOpen(jakarta.websocket.Session,jakarta.websocket.EndpointConfig)" class="member-name-link">onOpen</a><wbr>(<a href="../Session.html" title="interface