Create a ServerSocket : ServerSocket « Network « Java Tutorial

1. Java Tutorial
2. Network
3. ServerSocket

import java.io.IOException;
import java.net.ServerSocket;

public class MainClass {

  public static void main(String[] args) {

    try {
      ServerSocket server = new ServerSocket(0);
      System.out.println("This server runs on port " + server.getLocalPort());
    } catch (IOException ex) {
      System.err.println(ex);
    }
  }
}