I have application using CometD version 5 that does not support partial messages over websocket. Is it supported in newer version or else do i need to do it in my application. Any java libraries that provide partial messaging OOB with CometD
No support in CometD version 5. May consider upgrading the version 7 if it is supported or if third library exists
CometD does not support streaming of message content, as messages are formatted in JSON following the Bayeux protocol.
The typical case of wanting to stream content is for large contents, to reduce memory footprint.
Using messaging for large uploads/downloads is not really the use case for CometD: it would be far better to exchange an upload/download URI, and use HTTP (or even WebSocket, but with a different protocol than Bayeux) for the upload/download of large content.
If you specify what is exactly your use case, the answer could be more precise.