As Vassili pointed out, the <> are used in Generics, a language addition in Java version 1.5. It essentially allows the developer to create type declarations. I have found this especially helpful in the Collections framework. For example before 1.5 you might do something like the following:
Notice that I have to cast the return object from an Object to an Item. In Java 1.5 and later you can declare a list of a specific type:
See how you don't need to cast from an Object to an Item. And it also prevents non-Item type objects from being added to the list. Type safety is generally increased.
You might also check out the following tutorial: tutorial.