From Forum Nokia Wiki

net.rim.device.api.ui

Provides fundamental functionality for constructing the user interface of a RIM Device application

net.rim.device.api.ui.component

Provides a library of prebuilt interface components and controls for constructing usable UI applications

net.rim.device.api.ui.container

Provides a library of prebuilt interface component mangers for constructing usable UI applications

net.rim.device.api.ui.text

Provides classes to filter text strings containing various kinds of data.

net.rim.device.api.util

Provides a host of utility methods and intefaces useful within the context of the Device's system.

net.rim.device.api.collection

Defines basic functionality for data collections.

net.rim.device.api.collection.util

Provids a variety of collection implementations and utilities.

net.rim.device.api.compress

Provides components for compressing and uncompressing data.

net.rim.device.api.i18n

Provides functionality that supports the internationalization of applications on RIM Devices.

net.rim.device.api.io

Provides a library of components to manage data I/O.

net.rim.device.api.io.http

Http connection

net.rim.blackberry.api.browser

Provides access to the BlackBerry Browser application to create and display HTML or WML pages and to set browser options.

net.rim.blackberry.api.invoke

Allows third-party applications to remotely invoke internal applications

net.rim.blackberry.api.mail

Provides functionality for sending, receiving and accessing email messages using the BlackBerry Messages application.