 directly
 from <a href="../../javax/websocket/MessageHandler.Whole.html" title="interface in javax.websocket"><code>MessageHandler.Whole</code></a> or <a href="../../javax/websocket/MessageHandler.Partial.html" title="interface in javax.websocket"><code>MessageHandler.Partial</code></a>.
 In all other cases (Lambda Expressions, more complex inheritance or generic type arrangements),
 one of the following methods have to be used:
 <a href="../../javax/websocket/Session.html#addMessageHandler-java.lang.Class