Need to access/connect Remote Unix server from Java

Question

Please any one give me a direct solution for connecting a remote Unix server through telnet connection from java application. Thanks in advance..

Answer 1

If I run the below program codes, in the console it is asking to enter username and password in manual but I need to give it automatically.
The highlighted "root" is entered by the user manually using keyboard.
Expected:
I mean the username, password and some action is set to be automatic, so that it should not ask the user to enter the input from keyboard.
import java.awt.Robot;
import java.awt.event.KeyEvent;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.commons.net.telnet.TelnetClient;
import org.apache.commons.net.telnet.TelnetNotificationHandler;
import org.apache.commons.net.telnet.SimpleOptionHandler;
import org.apache.commons.net.telnet.EchoOptionHandler;
import org.apache.commons.net.telnet.TerminalTypeOptionHandler;
import org.apache.commons.net.telnet.SuppressGAOptionHandler;
import org.apache.commons.net.telnet.InvalidTelnetOptionException;
import java.util.StringTokenizer;
* This is a simple example of use of TelnetClient.
* An external option handler (SimpleTelnetOptionHandler) is used.
* Initial configuration requested by TelnetClient will be:
* WILL ECHO, WILL SUPPR
* ESS-GA, DO SUPPRESS-GA.
* VT100 terminal type will be subnegotiated.
* <p>
* Also, use of the sendAYT(), getLocalOptionState(), getRemoteOptionState()
* is demonstrated.
* When connected, type AYT to send an AYT command to the server and see
* the result.
* Type OPT to see a report of the state of the first 25 options.
* <p>
* @author Bruno D'Avanzo
public class UnixConnect implements Runnable, TelnetNotificationHandler
    static TelnetClient tc = null;
     * Main for the TelnetClientExample.
    public static void main(String[] args) throws IOException
        FileOutputStream fout = null;
        /*if(args.length < 1)
            System.err.println("Usage: TelnetClientExample1 <remote-ip> [<remote-port>]");
            System.exit(1);
        String remoteip = "192.168.20.11";
        int remoteport;
        if (args.length > 1)
            remoteport = (new Integer(args[1])).intValue();
        else
            remoteport = 23;
        try
            fout = new FileOutputStream ("spy.log", true);
        catch (Exception e)
            System.err.println(
                "Exception while opening the spy file: "
                + e.getMessage());
        tc = new TelnetClient();
        TerminalTypeOptionHandler ttopt = new TerminalTypeOptionHandler("VT200", false, false, true, false);
        EchoOptionHandler echoopt = new EchoOptionHandler(true, false, true, false);
        SuppressGAOptionHandler gaopt = new SuppressGAOptionHandler(true, true, true, true);
        try
            tc.addOptionHandler(ttopt);
            tc.addOptionHandler(echoopt);
            tc.addOptionHandler(gaopt);
        catch (InvalidTelnetOptionException e)
            System.err.println("Error registering option handlers: " + e.getMessage());
        while (true)
            boolean end_loop = false;
            try
                tc.connect(remoteip, remoteport);
                Thread reader = new Thread (new UnixConnect());
                tc.registerNotifHandler(new UnixConnect());
                reader.start();
                OutputStream outstr = tc.getOutputStream();
                byte[] buff = new byte[1024];
                int ret_read = 0;
                do
                    try
                        ret_read = System.in.read(buff);
                        if(ret_read > 0)
                        outstr.write(buff, 0 , ret_read);
                        outstr.flush();
                    catch (Exception e)
                        System.err.println("Exception while reading keyboard:" + e.getMessage());
                        end_loop = true;
                while((ret_read > 0) && (end_loop == false));
                try
                    tc.disconnect();
                catch (Exception e)
                          System.err.println("Exception while connecting:" + e.getMessage());
            catch (Exception e)
                    System.err.println("Exception while connecting:" + e.getMessage());
                    System.exit(1);
     * Callback method called when TelnetClient receives an option
     * negotiation command.
     * <p>
     * @param negotiation_code - type of negotiation command received
     * (RECEIVED_DO, RECEIVED_DONT, RECEIVED_WILL, RECEIVED_WONT)
     * <p>
     * @param option_code - code of the option negotiated
     * <p>
    public void receivedNegotiation(int negotiation_code, int option_code)
        String command = null;
        if(negotiation_code == TelnetNotificationHandler.RECEIVED_DO)
            command = "DO";
        else if(negotiation_code == TelnetNotificationHandler.RECEIVED_DONT)
            command = "DONT";
        else if(negotiation_code == TelnetNotificationHandler.RECEIVED_WILL)
            command = "WILL";
        else if(negotiation_code == TelnetNotificationHandler.RECEIVED_WONT)
            command = "WONT";
        System.out.println("Received " + command + " for option code " + option_code);
     * Reader thread.
     * Reads lines from the TelnetClient and echoes them
     * on the screen.
    public void run()
        InputStream instr = tc.getInputStream();
        try
            byte[] buff = new byte[1024];
            int ret_read = 0;
            do
                ret_read = instr.read(buff);
                if(ret_read > 0)
                   System.out.print(new String(buff, 0, ret_read));
            while (ret_read >= 0);
        catch (Exception e)
            System.err.println("Exception while reading socket:" + e.getMessage());
        try
            tc.disconnect();
        catch (Exception e)
            System.err.println("Exception while closing telnet:" + e.getMessage());