Content















 
Summary





This chapter focused on utility classes
of the Java API, particularly the collection classes. The collections
framework represents storage methods and behaviors prescribed for
collection objects. The framework is represented by six main
interfaces that determine collection behavior:

Collection
Set
List
SortedSet
SortedMap
Map

The essential differences between the
types are:

Collection objects impose no rules
on order or content duplication.
List maintains order.
Set rejects duplicate entries.
Maps uses unique keys to facilitate
lookup of their contents.

In addition to collections interfaces, the collection framework includes
implementations of these interfaces in classes such as ArrayList,
LinkedList, Vector, TreeMap, TreeSet, Hashtable, HashMap, and HashSet.
Furthermore, the Iterator is an interface for retrieving objects from
a collection. The iterator traverses the collection in one direction.
The ListIterator traverses the collection both backwards and forwards.