package com.gloomyfish.socket.tutorial.two; 
 
import java.io.DataOutputStream; 
import java.io.IOException; 
import java.net.ServerSocket; 
import java.net.Socket; 
 
public class HelloService extends Thread { 
  private ServerSocket serverSocket; 
  public HelloService(int port) throws IOException { 
    serverSocket = new ServerSocket(port); 
  } 
 
  public void run() 
  { 
    try { 
      while(true) 
      { 
        System.out.println("Waiting for client on port " + serverSocket.getLocalPort()); 
        Socket client = serverSocket.accept(); // blocked & waiting for income socket 
        System.out.println("Just connected to " + client.getRemoteSocketAddress()); 
        DataOutputStream dos = new DataOutputStream(client.getOutputStream()); 
        byte[] hello = "Hello, Java Socket".getBytes(); 
        dos.write(hello, 0, hello.length); 
        dos.close(); 
        client.close(); 
      } 
    } catch(Exception e) { 
      e.printStackTrace(); 
    } 
  } 
   
  public static void main(String[] args) { 
    try { 
      HelloService service = new HelloService(9999); 
      service.start(); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
  } 
} 

package com.gloomyfish.socket.tutorial.two; 
 
import java.io.DataInputStream; 
import java.io.IOException; 
import java.net.InetSocketAddress; 
import java.net.Socket; 
import java.net.SocketAddress; 
 
public class HelloClient { 
  private int clientNumber; 
  private SocketAddress address; 
  public HelloClient(int clientNum) { 
    clientNumber = clientNum; 
  } 
   
  public void setupClients(String serverHostName, int port) throws IOException { 
    address = new InetSocketAddress(serverHostName, port); 
    for(int i=0; i<clientNumber; i++) { 
      System.out.println(); 
      System.out.println("start client No. " + (i+1)); 
      Socket socket = new Socket(); 
      socket.connect(address); 
      DataInputStream bufferedReader = new DataInputStream(socket.getInputStream()); 
      byte[] cbuff = new byte[256]; 
      char[] charBuff = new char[256]; 
      int size = 0; 
      while( (size = bufferedReader.read(cbuff))> 0) { 
        convertByteToChar(cbuff, charBuff, size); 
        System.out.println(charBuff); 
      } 
      bufferedReader.close(); 
      socket.close(); 
    } 
  } 
   
  private void convertByteToChar(byte[] cbuff, char[] charBuff, int size) { 
    for(int i=0; i<charBuff.length; i++) { 
      if(i < size) { 
        charBuff[i] = (char)cbuff[i]; 
      } else { 
        charBuff[i] = ' '; 
      } 
    } 
     
  } 
 
  public static void main(String[] args) { 
    try { 
      HelloClient client = new HelloClient(10); 
      client.setupClients("localhost", 9999); 
    } catch (IOException e) { 
      e.printStackTrace(); 
    } 
  } 
}