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 ...

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

Java Platform, Standard Edition (Java SE) 5 introduced a new feature called generics that lets you specify the type of objects in collections.

The Java Platform provides the most commonly used data structures in the form of the Collections Framework, and it provides a rich API to operate on them. This article explains the concepts behind ...

The project's goals include a major overhaul of Java's generics, a new approach to generic typing, and new support for value types.

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.