IIS7 / asp.net / web.config protection for a file download

We have .JAR file and it loads on the user's machine via tag. Users can directly download the .JAR file via the URL if they view source and see .JAR filename. I tried to use "RequestFilter" option of IIS to deny .JAR but then the .JAR file does not work as the error is class not found. I had removed .JAR from the list of RequestFilter. Do you have a solution that the JAR file executes via the browser on the user's machine but nobody can download it directly? Love, Angel