Generics make your code more flexible and easier to read, and they help you avoid ClassCastExceptions at runtime. Get started with this introduction to using generics with the Java Collections ...

After five years of developer perseverance, generics are finally being added to the Java language. The path to generics has been frustrating and controversial to say the least. At JavaOne's ...

Generics can solve many more problems than collections. Use generics to write code once and reuse it more easily.

Apache Collections supports generics, so that's not a reason to choose one over the other. If the collections you need are available in it, I'd probably lean towards Guava, though.