I'm trying to figure out the difference between enterLocalActiveMode()/enterLocalPassiveMode() and enterRemoteActiveMode(InetAddress host, int port)/enterRemotePassiveMode() methods of FTPClient class from org.apache.commons.net.ftp.
I've only found some information about the difference between active and passive mode with FTP. But I don't understand the concept of local and remote previously mentioned.
The Apache Commons Net documentation (which you link yourself in the question) covers this.
In 99.9% cases, you want to use FTPClient.enterLocal*Mode. That's for client-server transfers.
The FTPClient.enterRemote*Mode is only for server-server transfers (aka FXP). What most FTP servers do not allow anyway.