FTPConnectionClosedException is used to indicate the premature or
unexpected closing of an FTP connection resulting from a
org.apache.commons.net.ftp.FTPReply.SERVICE_NOT_AVAILABLE FTPReply.SERVICE_NOT_AVAILABLE response (FTP reply code 421) to a
failed FTP command. This exception is derived from IOException and
therefore may be caught either as an IOException or specifically as an
FTPConnectionClosedException.
author: Daniel F. Savarese See Also:FTP See Also:FTPClient