On the server side of the whiteboard application, we have a class called Server. This class listens for incoming connections on a specified port. Each time a connection comes in, the Server creates a ConnectionProcessor to process the connection. Processing a connection means receiving text messages and sending them back out to other clients. The Server gives each client one ConnectionProcessor.

When a client first starts up, it initiates a connection to the server. The client keeps this connection open throughout the whiteboard session. Each text message is sent along this connection.

The figure below illustrates the client/server processes for the whiteboard application.