Why am I getting “Address already in use (Bind failed)”?

Question

This should be simple enough, but I am missing something here. I have two toy classes: (a) a server that expect connections and serves files; and (b) a client that requests a file and prints it out on the standard output.

Server code:

package lp2.tarefa4;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import static java.lang.String.format;
import java.net.ServerSocket;
import java.net.Socket;

public class ServidorWeb implements Runnable {

    private final String dirName;

    public ServidorWeb(String dirName) {
        this.dirName = dirName;
    }

    public static void main(String[] args) {
        ServidorWeb srv = new ServidorWeb(args[0]);
        srv.run();
    }

    @Override
    public void run() {
        System.out.println("Server started. Waiting for connections...");

        while (true) {
            try {
                ServerSocket server = new ServerSocket(48080);
                Socket socket = server.accept();
                proccessRequest(socket);
            }
            catch (IOException ex) {
                System.err.println("!!! ERRO: " + ex.getMessage());
            }
        }
    }

    private void proccessRequest(Socket socket) throws IOException {
        DataInputStream in = new DataInputStream(socket.getInputStream());
        DataOutputStream out = new DataOutputStream(socket.getOutputStream());
        String fileName = in.readUTF();
        File inputFile = new File(dirName, fileName);

        String msg = format("Request: %s:%d [%s]", 
                socket.getInetAddress(), 
                socket.getPort(), 
                inputFile.getPath());
        System.out.println(msg);

        DataInputStream fin = new DataInputStream(new FileInputStream(inputFile));
        String s = fin.readUTF();
        while (s != null) {
            out.writeUTF(s);
            s = fin.readUTF();
        }
        in.close();
        out.close();
        fin.close();
    }

}

Client code:

package lp2.tarefa4;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;

public class ClienteWeb implements Runnable {

    private final String host;
    private final int port;
    private final String fileName;

    public ClienteWeb(String host, int port, String fileName) {
        this.host = host;
        this.port = port;
        this.fileName = fileName;
    }

    public static void main(String[] args) {
        ClienteWeb srv = new ClienteWeb(args[0], Integer.parseInt(args[1]), args[2]);
        srv.run();
    }

    @Override
    public void run() {
        try {
            Socket socket = new Socket(host, port);
            DataInputStream in = new DataInputStream(socket.getInputStream());
            DataOutputStream out = new DataOutputStream(socket.getOutputStream());
            out.writeUTF(fileName);
            String s = in.readUTF();
            while (s != null) {
                System.out.println(s);
                s = in.readUTF();
            }
            in.close();
            out.close();
            socket.close();
        }
        catch (IOException ex) {
            System.err.println("!!! ERRO: " + ex.getMessage());
        }
    }

}

I am trying to run both, server and client, on the same machine, but every time I try to run the client always get this message from the server:

!!! ERRO: Address already in use (Bind failed)

Do I have to do anything different than the above to run this code without errors?

Thanks.

In your code, you should close ServerSocket as well – senseiwu Jun 23 '17 at 18:53 — senseiwu, Jun 23 '17 at 18:53

score 2 · Answer 1 · answered Jun 23 '17 at 17:48

The error usually means that the port you are trying to open is being already used by another application try using netstat to see which ports are open and then use an available port.

Also check if you are binding to the right ip address (I am assuming it would be localhost)

netstat -tulpn will enable one to find the process ID of that is using a particular port.

Why am I getting “Address already in use (Bind failed)”?

1 Answers1