在完成了傳送端與接收端的連線以後，可以進行雙方的雙向通訊，這裡的例子是SeverDemo在收到訊息後回覆一條訊息給ClientDemo。

程式碼：

ClientDemo.java

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;

public class ClientDemo {

	public static void main(String[] args) throws IOException{
		Socket s = new Socket("192.168.23.1", 10001);
		
		OutputStream os = s.getOutputStream();
		os.write("Can you read me?".getBytes());
		
		InputStream is = s.getInputStream();
		byte[] buf = new byte[1000];
		int length = is.read(buf);
		System.out.println("Information from " + s.getLocalAddress().getHostAddress() + " : " + new String(buf, 0, length));
		
		s.close();
	}
}
 

SeverDemo.java

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class SeverDemo02 {

	public static void main(String[] args) throws IOException{
		ServerSocket ss = new ServerSocket(10001);
		
		Socket s = ss.accept();
		InputStream is = s.getInputStream();
		byte[] buf = new byte[1000];
		int length = is.read(buf);
		System.out.println("Information from " + s.getLocalAddress().getHostAddress() + " : " + new String(buf, 0, length));
		
		OutputStream  os = s.getOutputStream();
		os.write("Very clear.".getBytes());
		
		s.close();
	}

}