> But this certainly requires an API defined at their end

Not certainly, screen scraping is always an option and which I guess is what the OP is looking for in this case given that it's a school project.

> it is difficult to find the information I need in the source code

As long as you don't abuse the service, XQuery and some other options can make your screen scraping a bit easier.

This involves a two step process:

• Construct a valid HTTP request along with the necessary parameters to query the kind of data you require. Take a look at the HttpClient API offered by Apache.
• Scrape the data from the response returned using various screen scraping techniques.