Major Description
ftp.FTPClient.initiateListParsing(String parserKey, String pathname) can call createFileEntryParser(String) with null systemName if the getSystemName() method fails.
The resulting ParserInitializationException does not identify the cause.
It would be better to throw a more specific error if the system name cannot be found.
Ideally, getSystemName() should throw the error, but that would change the documented behaviour (null is specifically allowed as a return value).
As it happens, getSystemName() is badly named, so one way forward is to create a new method getSystemType() which never returns null.
Can then deprecate getSystemName().