Once a connection is established and you have an instance of either
websocket4j.server.WebSocket you can use them in uniform way to
send and receive messages.
Throughout this chapter
WebSocket will refer to both
To send messages you can use
sendMessage(String) : void method of
WebSocket. This method immediately sends given string to the other
To receive messages you can use synchronous
String method of WebSocket. This method waits until the other party
sends a message and then returns it.