Ant

 Source for build.xml 
 Source for the ftp download client 
https://www.codejava.net/java-se/ftp/java-ftp-list-files-and-directories-example
https://commons.apache.org/proper/commons-net/apidocs/org/apache/commons/net/ftp/FTPClient.html
https://www.codejava.net/java-se/ftp/java-ftp-example-get-details-of-a-file-or-directory-on-server
https://www.geeksforgeeks.org/date-gettime-method-in-java-with-examples/   (Convert calendar to date)
java unix time http://zetcode.com/java/unixtime/
https://mkyong.com/java/how-to-get-the-file-last-modified-date-in-java/#