Collections in Java

Collection Framework

Introduction to the Collections Framework

Collection Interfaces

Iterator Interface

Group Operations

AbstractCollection Class

Collection Framework Design Concerns

Set Interface

HashSet, TreeSet Classes

List Interface

Map interface

Sorting

Historical Collection Classes

Objective

At the end of this chapter, you will be able to:

Learn about the implementation of Collection Interfaces:

Understand the Iterator Interface and Group Operation

Know in details about the AbstractCollection Class

Prepare yourself for Collection Framework Design Concerns

Gain knowledge about the Set Interface

Get some ideas about the HashSet, TreeSet Classes

Deal with List Interface, Map interface and Sorting

Have a basic idea about Historical Collection Classes such as

Dictionary, Hashtable and Properties Classes

Collections Overview

This chapter deals with one of the powerful subsystems: Collections. Collections provide a

well-defined set of interfaces and classes to store and manipulate groups of data as a

single unit. This unit is called a collection.

The framework provides a convenient API to many of the abstract datatypes like maps,

sets, lists, trees, arrays, hashtables and other collections. The Java classes in the

Collections Framework encapsulate both the data structures and the algorithms associated

with these abstractions because of their object-oriented design.

The framework provides a standard programming interface to many of the most common

abstractions, without complicating it with too many procedures and interfaces. The

programmer can easily define higher-level data abstractions like stacks and queues with

the help of a variety of operations supported by the collections framework.

The major goals of the Collections Framework are: High-performance. Implementations for