question: public sun . net . ftp . FtpClient login ( String user , char [ ] password , String account ) throws sun . net . ftp . FtpProtocolException , IOException { if ( ! isConnected ( ) ) { throw new sun . net . ftp . FtpProtocolException ( "Not connected yet" , FtpReplyCode . BAD_SEQUENCE ) ; } if ( user == null || user . length ( ) == 0 ) { throw new IllegalArgumentException ( "User name can't be null or empty" ) ; } tryLogin ( user , password ) ; if ( lastReplyCode == FtpReplyCode . NEED_ACCOUNT ) { issueCommandCheck ( "ACCT " + account ) ; } StringBuffer sb = new StringBuffer ( ) ; if ( serverResponse != null ) { for ( String l : serverResponse ) { if ( l != null ) { if ( l . length ( ) >= 4 && l . startsWith ( "230" ) ) { l = l . substring ( 4 ) ; } sb . append ( l ) ; } } } welcomeMsg = sb . toString ( ) ; loggedIn = true ; return this ; }
target:  Attempts to log on the server with the specified user name, password and account name.