The two examples discussed so far use high-level Java networking capabilities to communicate between applications. In the examples, it was not your responsibility to establish the connection between a client and a server. The first program relied on the web browser to communicate with a web server. The second program relied on a JEditorPane to perform the connection. This section begins our discussion of creating your own applications that can communicate with one another.
Establishing a simple server in Java requires five steps.Step 1 is to create a Server-Socket object. A call to the ServerSocket constructor, such as
ServerSocket server = new ServerSocket( portNumber, queueLength );