Finally, you could look at a textbook for a language that already supports generics. Here is the list . I regret to say that it's not an oversight. When the powers that be were deciding what to pursue, they came to the conclusion that there was no business case for adding Generics to Merlin. If you feel that it's important to add them to Merlin, make your voice heard.
Public review is underway.
It seems like something could be done about this, and I've hacked more typesafe ways, but I wish this could be looked at in more detail. I am downloading a url in a loop. Just let the GC do what it's good at. This is also beyond my area of expertise. I believe that it is possible with the DataFlavor API, but that there are limitations.