Recently I was been assigned to write a FTP layer for a project at work.It needed to be supported all the funky FTP stuff like active,passive mode all kind of proxies like FTP,HTTP,SOCKS…etc.
At first I was little worried cause even in Apache Commons Net, it doesn’t support clear architecture for all those weird FTP stuff.Then I came up with this library FTP4J which saved my life.
FTP4J is well designed and easy to use library and best thing is its open-source and comes with LGPL license.
Ashika learns to blog 
Still I am having a very bad time because of FTP4J.
Also I found difficulties when uploading files to yahoo ftp servers and there were several issues when connecting to ftp severs which does support REST command.
The execution is not stable for yahoo ftp servers
I am not getting any help for ftp4j. Like sample codes or examples and one more thing.
I think it doesn’t support SFTP at least I did not find any such class in the API…………