Collection Service (Java Enterprise in a Nutshell)

11.15. Collection Service

The Collection Service supports the grouping of objects into various types of collections, such as sets, queues, and sequences. The service also includes representations for iterators of these collections and for operations to be performed to elements of a collection.

The Collection interface is the root of a large family of subclasses that define specific types of collections, such as Set, Heap, Stack, Queue, SortedSet, etc. There are also factory classes for these that allow you to create collections of each type. Similarly, the Iterator interface is the root of the hierarchy of iterator types, such as EqualityIterator and SequentialIterator. The Operations interface is provided as a base class for any operation a user may perform on a collection.