code: public void retrieveFile(String remotePath, String localPath)
              throws FileNotFoundException, IOException {
          FileOutputStream localFileOutputStream =
                  new FileOutputStream(localPath);
          ftpClient.retrieveFile(remotePath, localFileOutputStream);
          localFileOutputStream.close();
      }
docs: Retrieves a file, specified by {@code remotePath}, from the ftp server
  and saves it locally to {@code localPath}.
  
  @param remotePath {@link String}, the remote path
  @param localPath {@link String}, the local path
  @throws FileNotFoundException - Thrown if the file exists but is a directory
  rather than a regular file, does not exist but cannot be created,
  or cannot be opened for any other reason.
  @throws IOException - Thrown if an io error occurred saving the
  {@code remotePath} to {@code localPath}.