The org.red5.net.websocket.server.DefaultWebSocketEndpoint, can be extended in your application. Your extended class must be placed in the lib directory of your Red5 server, (not the webapps/yourapp/WEB-INF/lib directory). In addition, in your webapp descriptor webapps/yourapp/WEB-INF/web.xml file, an entry named wsEndpointClass will need to be made for your class:

    <context-param>
        <param-name>wsEndpointClass</param-name>
        <param-value>com.mydomain.websocket.MyWebSocketEndpoint</param-value>
    </context-param>

One reason to extend the endpoint for your own use could be because the default endpoint implementation only handles text data.