I'm using Apache Camel as an integration platform. Specifically, at the moment, I depend on the ftp/ftps/sftp support in the camel-ftp component. Under the hood Camel uses Commons Net for ftp and ftps support.
Recently, the camel-ftp component was enhanced (on my request) with the possibility to use a secure data channel. This is accomplished by using the execProt() (and execPsbz()) method in class FTPSClient.
However, later on (in case Camel needs to reconnect), one of the connect() methods in the base class to FTPSClient is called. Unfortunately all the connect methods first create an unconnected socket and then tries to connect it. The connection factory now associated with the FTPSClient then throws an exception stating: "Unconnected sockets not implemented".
It seems like the FTPSClient does not support "re-connect" once it has entered secure communications mode.