Java HEAD/GET request versus Linux request

Hopefully it's a simple question. I am trying to make a HEAD/GET request to a university server, making sure the server even exists. The HEAD request sends first, and if that fails we send a GET request. Unfortunately, both requests are returning 403's. This is using a little Java program I made.

Now when I use Linux to send HEAD/GET requests, I get a 200 response with both. So what is the deal here? Is there a difference in information requested with Java compared to Linux? Thank you in advance for anything!