Java™ How to Program, Seventh Edition

19.2. Collections Overview

A collection is a data structure—actually, an object—that can hold references to other objects. Usually, collections contain references to objects that are all of the same type. The collections framework interfaces declare the operations to be performed generically on various types of collections. Figure 19.1 lists some of the interfaces of the collections framework. Several implementations of these interfaces are provided within the framework. Programmers may also provide implementations specific to their own requirements.

Figure 19.1. Some collection framework interfaces.

Interface	Description
Collection	The root interface in the collections hierarchy from which interfaces Set, Queue and List are derived.
Set	A collection ...