I have an SFTP connection set up. I used WinCSP and Filezilla and the test server is working no problem. The java code is from the apache commons-net 2.0 and it
apache commons-net 2.0
Since you are connecting to an SSH server using FTP client. FTPS and SFTP are two different protocols.
Both WinSCP and Filezilla works fine because they supports SFTP.