Error: java.net.SocketException: Connection reset

[Heg Lachher]

This error happens whenever a client connects to my server.
Here is my code:

Server:

import java.net.*;
import java.io.*;
public class Serv {
	private static int port = 0;
	private static String intput = "";
	public static void main(String[] args) {
		if (args.length == 1) {
			try {
				port = Integer.parseInt(args[0]);
			} catch (NumberFormatException e) {
				System.err.println("Please enter a valid number");
			} catch (Exception e) {
				System.err.println("Error: "+e);
			}	
			ServerStart();
		} else {
			System.err.println("Usage: java Serv <port>");
		}
	}
	public static void ServerStart() {
		Socket server = null;
		try {	
			ServerSocket listener = new ServerSocket(port);
			server = listener.accept();
	    	DataInputStream  in = new DataInputStream(server.getInputStream());
	        PrintStream echo = new PrintStream(server.getOutputStream());
	        while((intput = in.readLine()) != null && !intput.equals(".")) {
	        	System.out.println(intput);
	            echo.println("Echoed: "+intput);
	          }
	        server.close();
	    } catch (ConnectException e) {
			System.out.println("Port already in use");
		} catch (IOException ioe) {
	    	System.err.println("Error: "+ioe);
	    } catch (Exception e) {
	    	System.out.println("Error: "+e);
	    }
	}
}

Client:

import java.io.*;
import java.net.*;
public class Client {
	public static void main(String[] args) {
		if (args.length == 2) {
			try {
			Socket server = new Socket(args[0], Integer.parseInt(args[1]));
			} catch (NumberFormatException e) {
				System.out.println("Enter a valid port");
			} catch (Exception e)  {
				System.out.println("Error: "+e);
			}
		} else {
			System.out.println("Usage: java Client <Client> <Port>");
		}
	}
	public static void startServer(Socket server) {
		String str = "";
		try {
			BufferedReader inUser = new BufferedReader(new InputStreamReader(System.in));
			DataOutputStream out = new DataOutputStream(server.getOutputStream());
			BufferedReader in = new BufferedReader(new InputStreamReader(server.getInputStream()));
			while ((str = inUser.readLine()) != null && !str.equals(".")) {
				out.writeBytes("Recieved: "+str);
				System.out.println(in.readLine());
			}
			server.close();
		} catch (Exception e) {
			System.out.println("Error: "+e);
		}
	}
}

Output:
Server:
Error: java.net.SocketException: Connection reset
Client:
<nothing>
Help appreiciated!
Me:

[narendra darlanka]

Hi,
You are closing the Socket in your client program as soon as you open it ,causing the Server side streams to close abruptly. Change your client code to write something to the stream .

    Socket server = new Socket(args[0], Integer.parseInt(args[1]));  
                server.getOutputStream().write("2\n".getBytes());

This would cause the server to print the value and then throw the reset exception(since the client is terminated)
Also note that since you are using the readLine() at the server, you must terminate the string at the client side with a new line

a good java trail for starting client server programming http://docs.oracle.com/javase/tutorial/networking/sockets/clientServer.html

[narendra darlanka]

Hi,
You are closing the Socket in your client program as soon as you open it ,causing the Server side streams to close abruptly. Change your client code to write something to the stream .

    Socket server = new Socket(args[0], Integer.parseInt(args[1]));  
                server.getOutputStream().write("2\n".getBytes());

This would cause the server to print the value and then throw the reset exception(since the client is terminated)
Also note that since you are using the readLine at the server, you must terminate the string at the client side with a new line

a good java trail for starting client server programming http://docs.oracle.com/javase/tutorial/networking/sockets/clientServer.html

[Heg Lachher]

See below below

[Heg Lachher]

See below

[Heg Lachher]

I found out the problem!
The code totally works!
I just didn't call the startServer(Socket server) method

Old code:

public class Client {
	public static void main(String[] args) {
		if (args.length == 2) {
			try {
			Socket server = new Socket(args[0], Integer.parseInt(args[1]));
			} catch (NumberFormatException e) {
				System.out.println("Enter a valid port");
			} catch (Exception e)  {
				System.out.println("Error: "+e);
			}
		} else {
			System.out.println("Usage: java Client <Client> <Port>");
		}
	}

New code:

public class Client {
	public static void main(String[] args) {
		if (args.length == 2) {
			try {
			Socket server = new Socket(args[0], Integer.parseInt(args[1]));
			startServer(server); //This is not in the old code
			} catch (NumberFormatException e) {
				System.out.println("Enter a valid port");
			} catch (Exception e)  {
				System.out.println("Error: "+e);
			}
		} else {
			System.out.println("Usage: java Client <Client> <Port>");
		}
	}

[narendra darlanka]

The problem is in your client program,you are not calling the startServer method (line 08). Another problem you would have is , on the client side you are using an writeBytes() which would not add a terminating new line ,whereas you are expecting
newline terminate string by using readLine() . to fix it you can append the new line manually before writing to the output stream (line 25 "+"\n" )

    import java.io.*;  
    import java.net.*;  
    public class Client {  
        public static void main(String[] args) {  
            if (args.length == 2) {  
                try {  
                Socket server = new Socket(args[0], Integer.parseInt(args[1]));  
                     startServer(server)   //  <--missing 
                } catch (NumberFormatException e) {  
                    System.out.println("Enter a valid port");  
                } catch (Exception e)  {  
                    System.out.println("Error: "+e);  
                }  
            } else {  
                System.out.println("Usage: java Client <Client> <Port>");  
            }  
        }  
        public static void startServer(Socket server) {  
            String str = "";  
            try {  
                BufferedReader inUser = new BufferedReader(new InputStreamReader(System.in));  
                DataOutputStream out = new DataOutputStream(server.getOutputStream());  
                BufferedReader in = new BufferedReader(new InputStreamReader(server.getInputStream()));  
                while ((str = inUser.readLine()) != null && !str.equals(".")) {  
                    out.writeBytes("Recieved: "+str+"\n");  
                    System.out.println(in.readLine());  
                }  
                server.close();  
            } catch (Exception e) {  
                System.out.println("Error: "+e);  
            }  
        }  
    }  

Since you are dealing with just strings, i think an alternative better way to handle it would be to just use a PrintWriter

        public static void startServer(Socket server) {  
            String str = "";  
            try {  
                BufferedReader inUser = new BufferedReader(new InputStreamReader(System.in));  
                
                //DataOutputStream out = new DataOutputStream(server.getOutputStream());  
                PrintWriter out  = new PrintWriter(server.getOutputStream());
                BufferedReader in = new BufferedReader(new InputStreamReader(server.getInputStream()));  
                while ((str = inUser.readLine()) != null && !str.equals(".")) {  
                	
                    //out.writeBytes("Recieved: "+str+"\n");
                    out.println("Recieved: "+str);
                    out.flush();
                    System.out.println("...."+str);
                    System.out.println(in.readLine());  
                }  
                server.close();  
            } catch (Exception e) {  
                System.out.println("Error: "+e);  
            }  
        }