20.2. 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 20.1 lists some of the interfaces of the collections framework. Several implementations of these interfaces are provided within the framework. You may also provide implementations specific to your own requirements.