Core Java™ 2 Volume II - Advanced Features, Seventh Edition

Implementing Servers

Now that we have implemented a basic network client that receives data from the Internet, let's implement a simple server that can send information to clients. Once you start the server program, it waits for some client to attach to its port. We chose port number 8189, which is not used by any of the standard services. The ServerSocket class establishes a socket. In our case, the command

ServerSocket s = new ServerSocket(8189);

establishes a server that monitors port 8189. The command

Socket incoming = s.accept();

tells the program to wait indefinitely until a client connects to that port. Once someone connects to this port by sending the correct request over the network, this method returns a Socket object that represents ...