Re: [jetty-dev] Java WebSocket Client from main(String  args)
Which version of Jetty are you attempting to connect to?
The error message you got is the server saying that you didn't provide a Sec-WebSocket-Version request header that it recognized.
Note: this error message text has been cleaned up for the next release of Jetty 7 and Jetty 8.
It could be that either you are not sending this request header, or that the server is configured to not support the version you are specifying.
In recent versions of Jetty 7 and Jetty 8, there is a "minVersion" init-param on the servlet that can control this minimum supported websocket version. (if you have access to the server, set that to "-1" to enable all versions of websocket, even draft versions)