How can I get the filesystem path of the JSP from a servlet?

It's proving to be a tedious issue for me. I'm trying to make a dynamic web page which requires me to populate a dropdown menu with items that are dynamically generated from an executable on the server. The executable is local relative to the JSP in the filesystem.

I know that it can be done because I can run an executable with:

<form action="./my_executable">

But if I try doing this from a JSP Servlet (something I'm required to do), the:

<%= new File("./my_executable").getPath() %>

Gives me a different path in the filesystem entirely.