Inspect this method please.

Question

Hello,
I would greatly appreciate some feedback on this method. The method is part of a class that is part of a project called FileSwap which I am developing in school. (My first networking app)
Please ignore any syntax errors (I just wrote this up and haven't compiled...), and assume that a connection is established and all variables have been properly initialized. I am only looking for feedback on the meat of the method and logic, mainly reading from the socket and writing to a file. Lastly, the method is by no means complete...
Thanks in advance...
// FileSwap - receiveFile()
private final int LENGTH_TO_READ = 1024;
private String lastFileRequested;   // set for every sendCommand() not containing "List"
private String separator;          // dependent on OS
private String sharedDirectoryPath;
byte[] bytesRead;
InputStream is;
BufferedInputStream bis;
FileOutputStream fos;
Socket fsSocket;
public void receiveFile()
     // Before saving the file, verify to overwrite if it already exists
     int overwrite;
     File testOverwrite = new File(sharedDirectoryPath + separator + lastFileRequested);
     if (testOverwrite.exists())
          overwrite = JOptionPane.showConfirmDialog(
               null,
                  ("File: " + lastFileRequested + " already exists. Overwrite?"),
               "Message from FileSwap.",
               YES_NO_OPTION);
          if (overwrite == JOptionPane.YES_OPTION)
               // Save the file
               try
                    fos = new FileOutputStream(sharedDirectoryPath + separator + lastFileRequested);
                    bytesRead = new byte[LENGTH_TO_READ];
                    // Get the sockets input stream
                    is = new InputStream(fsSocket.getInputStream());
                    bis = new BufferedInputStream(is, LENGTH_TO_READ);
                    // read the bytes, write them to a new file
                    while ((lengthRead = bis.read(bytesRead, 0, LENGTH_TO_READ) != -1)
                         fos.write(bytesRead, 0, lengthRead);
               catch (IOException ioe)
                    JOptionPane.showMessageDialog(null, ioe.getMessage());
               // TODO: cleanup
          else
               // Do not overwrite, save new or discard...
               // TODO
     else     
          // File doesn't exist, just save it
          try
               fos = new FileOutputStream(sharedDirectoryPath + separator + lastFileRequested);
               // Get the sockets input stream
               is = new InputStream(fsSocket.getInputStream());
               bis = new BufferedInputStream(is, lengthToRead);
               // read the bytes, write them to a new file
               while ((lengthRead = bis.read(bytesRead, 0, lengthToRead) != -1)
                    fos.write(bytesRead, 0, lengthRead);
          catch (IOException ioe)
               JOptionPane.showMessageDialog(null, ioe.getMessage());
          // TODO: cleanup
}

Answer 1

If I use a buffer larger than 8192, I would have to set the socket receive buffer to reflect this... correct?Not necessarily. Large socket receive buffers always help, but there's no necessary connection between the size of the application buffer and the size of the socket receive buffer. The reason I said 8192 is that BufferedInputStream has an 8192 byte buffer.
This would also prove to be much faster when downloading large files... correct?Definitely, and in this case the larger the socket receive buffer the better. Set it to 64k-1.