The CometD libraries allow your application to send messages in three forms: Push-Subscribe, Peer-to-Peer and Remote-Call.
With Publish-Subscribe, a message sent by a publisher is broadcast to many subscribers. This is the typical case for chat rooms, for example.
With Peer-to-Peer, a message is sent by a sender to a specific receiver. This is the typical case for private one-to-one chats, for example.
With Remote-Call, a “message” is sent by a client to the server to perform a specific action. This is the typical case for creating a new chat room, for example.
Learn more about the CometD messaging features in the reference manual.