I am getting java.net.UnknownHostException

[Samanthi perera]

here is my socket example

import java.io.*;
import java.net.*;

public class EchoClient {
    public static void main(String[] args) throws IOException {

        Socket echoSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            echoSocket = new Socket("taranis", 7);
            out = new PrintWriter(echoSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(
                                        echoSocket.getInputStream()));
        } catch (UnknownHostException e) {
        	e.printStackTrace();
            System.err.println("Don't know about host: taranis.");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for "
                               + "the connection to: taranis.");
            System.exit(1);
        }

	BufferedReader stdIn = new BufferedReader(
                                   new InputStreamReader(System.in));
	String userInput;

	while ((userInput = stdIn.readLine()) != null) {
	    out.println(userInput);
	    System.out.println("echo: " + in.readLine());
	}

	out.close();
	in.close();
	stdIn.close();
	echoSocket.close();
    }
}

when i run this programm i am getting this error

java.net.UnknownHostException: taranis
	at java.net.PlainSocketImpl.connect(Unknown Source)
	at java.net.SocksSocketImpl.connect(Unknown Source)
	at java.net.Socket.connect(Unknown Source)
	at java.net.Socket.connect(Unknown Source)
	at java.net.Socket.<init>(Unknown Source)
	at java.net.Socket.<init>(Unknown Source)
	at EchoClient.main(EchoClient.java:12)
Don't know about host: taranis.

i got this example from this URL
http://java.sun.com/docs/books/tutorial/networking/sockets/readingWriting.html

[Ulf Dittmer]

This has nothing to do with that particular problem, but there's another one lurking: Don't println to a Socket

[Samanthi perera]

what do you mean nothing to do.Still i am getting error?

[Paul Clapham]

Right. You're trying to connect to a computer named "taranis" but there's no such computer in your network. Talk to the person who manages your network and ask them to explain to you the basics of how computer networks work.

[Samanthi perera]

I don't have a networ here.there is only one computer.can't we check socket using localhost?

[Ulf Dittmer]

If you don't have a network, how do you propose to connect to another computer?

[Samanthi perera]

can't we use a same machine to do this?i mean localhost

[Jaikiran Pai]

Samanthi perera wrote:can't we use a same machine to do this?i mean localhost

echoSocket = new Socket("taranis", 7);

What is "taranis"

[Jaikiran Pai]

Samanthi perera wrote:

i got this example from this URL
http://java.sun.com/docs/books/tutorial/networking/sockets/readingWriting.html

You seem to have literally copied that example and did not even read what those lines of code are meant for. There's an explanation about the code on that page. It even tells what the first param "taranis" is. Have you read that?