The JavaTM Tutorial
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Trail: Overview
Lesson: Overview

Essential Classes

The collections and internationalization APIs are essential to most enterprise applications.

Collections

A collection, or container, consists of multiple objects grouped into a single object. Normally collections represent data items that form a natural group, such as names and addresses or resumes.

The collections API includes a framework, which is a unified architecture for representing and manipulating collections of objects independent of their representation details. Collections enable interoperability between unrelated API, encourage software reuse, and make it easier to design, implement, or learn a new API.

Collections were added in JDK 1.2.

Internationalization

Internationalization lets you design an application so it can be adapted to many languages and regions without recompiling. The textual data, such as messages and GUI component labels, and other culturally dependent data, such as dates and currencies, are isolated from the rest of the application in sets of files, with one set containing the text for a given language and region. For example, a single application might have a set of files for French and another set for Canadian French; because the language code is specified at runtime, the same application can be distributed to Canada and to France with no modifications to the executable code. By isolating the text to be translated, you also save translation costs.

In JDK 1.2 changes to the internationalization API include the addition of the input method framework and a number of surface changes that involved renaming and moving methods and changing the order of method parameters for simplification.


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