How can we use Backed Collections in java?

Well, a backed collection is a collection which uses another collection for its storage.

This means that if you change an element in the original collection, it will automatically change the corresponding element in the backed collection (and vice versa) because they're the same element.

You can't usually tell from the name whether a collection is backed or not - you have to consult the documentation.

Check this link for a simple example of backed collections:

http://newjavafaqs.blogspot.co.uk/2011/03/what-is-backed-collection.html