Websockets is not enabled in GlassFish 3.1 by default. Yet if an application starts using grizzly websocket
APIs, no error is reported whatsoever. Please provide some hint to the user via, say, a log message.
Any for anyone reading this, this is how to turn WebSockets on:
asadmin set configs.config.server-config.network-config.protocols.protocol.http-listener-