Java servlets

I am beginning to use servlets through an Apache web server. I understand how the servlet interacts with the posts from the web page users overall, but I am not sure of how to handle multiple selection boxes. How do you receive all of the responses from the post for the multiple selections? How do they come through? (As comma seperated with the variable name listed once, or as seperate entries with the same variable name) Any help is appreciated.

Jeremy