Is there currently a way out there to convert CSV files to the OpenTSDB format? It was suggested to me to write a custom Java program to do this conversion, but I'm not really sure where to start there. Any help would be appreciated.
First, I would create a class that can read from that CSV, you can use OpenCSV library, you can find information all around the internet regarding that library. And after that extract what you need (if you have to - I am not sure if you only want simply just convert or to parse the file and get info from inside the file.) And then you have to know your OpenTSDB format and do the magic you have to do. Your question is a bit too general, can you be more specific? You have the link with the OpenTSDB documentation here.
Hopefully I have helped you a bit.