code: private Map<String, Long> listFiles() throws FtpException {
  		int attempts = 0;
  		Map<String, Long> files = new LinkedHashMap<String, Long>();
  		while (true){
  			try {
  				FTPListParseEngine engine = null;
  				if (type.startsWith("UNIX")) {
  					engine = ftpClient.initiateListParsing(FTPClientConfig.SYST_UNIX, null);
  				} else {
  					engine = ftpClient.initiateListParsing();
  				}
  
  				FTPFile[] list = engine.getFiles();
  				if (list != null){
  					for (FTPFile ftpFile : list){
  						files.put(ftpFile.getName(), ftpFile.getSize());
  					}
  				}
  				return files;
  			} catch (Exception e) {
  				attempts++;
  				if (attempts > 3) {
  					throw new FtpListFilesException(e);
  				} else {
  					LOGGER.trace("First attempt to get list of files FAILED! attempt={}", attempts);
  				}
  			}
  		}
  	}
docs: List files inside the current folder.
  
  @return List with files names and size
  @throws IOException