ServerSocket

A server program begins by creating a new ServerSocket object to listen on a specific port.

try {
    serverSocket = new ServerSocket(4444);
} catch (IOException e) {
    System.out.println("Could not listen on port: 4444");
    System.exit(-1);
}

Next, call the accept() method to wait for client connection request.

Socket clientSocket = null;
try {
    clientSocket = serverSocket.accept();
} catch (IOException e) {
    System.out.println("Accept failed: 4444");
    System.exit(-1);
}

Similar to the client program, create your input and output stream classes.

PrintWriter out = new PrintWriter(
    clientSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(
    new InputStreamReader(clientSocket.getInputStream()));