what does <Elements> mean

[JordashTalon]

Looking at this:

private Collection<Element> elements = new ArrayList<Element>();


What does that do?

[Fubarable]

This is how Java implements generics, a new feature in Java 5, I think, and it allows for increased compile-time type safety. For details, please have a look here:
Lesson: Generics (The Java™ Tutorials > Bonus)