Collections hirarchy

We have tried you to make a walk through the Collection Framework. The Collection Framework provides a well-designed set if interface and classes for sorting and manipulating groups of data as a single unit, a collection.

The Collection Framework provides a standard programming interface to many of the most common abstractions, without burdening the programmer with too many procedures and interfaces.

The Collection Framework is made up of a set of interfaces for working with the groups of objects. The different interfaces describe the different types of groups. For the most part, once you understand the interfaces, you understand the framework. While you always need to create specific, implementations of the interfaces, access to the actual collection should be restricted to the use of the interface methods, thus allowing you to change the underlying data structure, without altering the rest of your code.