Address already in use (bind failed)

Question

I'm using these two java sources to exchange a file between 2 PC(linux and mac). The problem is showed only on Linux.

I'm using these 2 codes in a thread where i recall more times.

But i have this error: Address already in use (bind failed). I have searched on the web and on this forum that the problem is the TCP connection still active, so there is a function of the class Server Socket called setReuseAddress(true) which allows me to reuse the address. I call this function after the instantiation of ServerSocket but the problems persists. How can i resolve this problem?

[EDIT] Server

{

        final int SOCKET_PORT = 13267;
        final String FILE_TO_SEND = "/Users/jo/Desktop/cryptedSymmetric.key";
        boolean flag = true;
        FileInputStream fis = null;
        BufferedInputStream bis = null;
        OutputStream os = null;
        ServerSocket servsock = null;
        Socket sock = null;

        try {
            servsock = new ServerSocket(); // create unbound ServerSocket
            servsock.setReuseAddress(true);
            servsock.bind(new InetSocketAddress(SOCKET_PORT));

            // while (flag) {
            System.out.println("SO_REUSEADDRESS is enabled: " + servsock.getReuseAddress());
            System.out.println("Waiting client B...");
            try {
                sock = servsock.accept();
                System.out.println("Connection : " + sock);
                // send file
                File myFile = new File(FILE_TO_SEND);
                byte[] mybytearray = new byte[(int) myFile.length()];
                fis = new FileInputStream(myFile);
                bis = new BufferedInputStream(fis);
                bis.read(mybytearray, 0, mybytearray.length);
                os = sock.getOutputStream();
                System.out.println("Invio del file " + FILE_TO_SEND + "(" + mybytearray.length + " bytes)");
                os.write(mybytearray, 0, mybytearray.length);
                os.flush();
                System.out.println("Done.");
                flag = false;
            } finally {
                if (bis != null)
                    bis.close();
                if (os != null)
                    os.close();
                if (sock != null)
                    sock.close();
            }
            // }
        } finally {
            if (servsock != null)
                servsock.close();

            return flag;
        }
    }

EDIT Client

{
        int SOCKET_PORT = 0;
        SOCKET_PORT = 13267;
        // final String SERVER = "192.168.1.2";
        final String FILE_TO_RECEIVED = "/Users/jo/Desktop/publicB.key";
        final int FILE_SIZE = 6022386;
        boolean flag = true;

        int bytesRead;
        int current = 0;
        FileOutputStream fos = null;
        BufferedOutputStream bos = null;
        Socket sock = null;
        try {
            sock = new Socket(address.getHostAddress(), SOCKET_PORT);
            System.out.println("Connessione...");

            // receive file
            byte[] mybytearray = new byte[FILE_SIZE];
            InputStream is = sock.getInputStream();
            fos = new FileOutputStream(FILE_TO_RECEIVED);
            bos = new BufferedOutputStream(fos);
            // bytesRead = is.read(mybytearray, 0, mybytearray.length);
            // current = bytesRead;
            int count;
            while ((count = is.read(mybytearray)) > 0) {
                bos.write(mybytearray, 0, count);
            }



            bos.flush();
            System.out.println("File " + FILE_TO_RECEIVED + " scaricato (" + current + " bytes letti)");
            flag = false;
        } finally {
            if (fos != null)
                fos.close();
            if (bos != null)
                bos.close();
            if (sock != null)
                sock.close();

            return flag;

        }

    }

user207421 user207421 · Accepted Answer · 2017-10-20T00:56:56

I call this function after the instantiation of ServerSocket but the problems persists.

That's because you called it too late. You should have observed that the exception was thrown before the call. You need to separate creation from binding:

servsock = new ServerSocket(); // create unbound ServerSocket
servsock.setReuseAddress(true);
servsock.bind(new InetSocketAddress(SOCKET_PORT));

NB your copy code should be the same at both ends, and not like either version you've used, which exhibit various problems and fallacies:

while ((count = in.read(buffer)) > 0)
{
    out.write(buffer, 0, count);
}

Address already in use (bind failed)

1 Answers