Problem with FTPClient class in java

Question

I\'m using org.apache.commons.net.ftp.FTPClient and seeing behavior that is, well... perplexing.

The method beneath intends to go through an FTPFile list, read them

Answer 1

According to the API for FTPClient.retrieveFileStream(), the method returns null when it cannot open the data connection, in which case you should check the reply code (e.g. getReplyCode(), getReplyString(), getReplyStrings()) to see why it failed. Also, you are suppose to finalize file transfers by calling completePendingCommand() and verifying that the transfer was indeed successful.