01 dmaj session 01a

8/6/2019 01 DMAJ Session 01A

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Slide 1 of 22Ver. 1.0

Developing Mobile Applications Using Java

The availability of wireless Internet services on mobile

devices is making communication possible anywhere and at

anytime.

Java offers a flexible and robust platform for mobile

application development with enterprise-class performance,reliability, and value.

Java Micro Edition (Java ME) allows developers to use the

Sun Java wireless toolkit to create applications and

programs for wireless and mobile devices.

The Developing Mobile Applications Using Java courseenables you to develop, debug, test, and securely deploy

mobile applications by using Java ME.

Rationale


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Introduction to Mobile Application Development

Mobile applications are developed for handheld devices,

such as mobile phones and Personal Digital Assistants

(PDAs).

At present, several platforms such as Java Micro Edition

(Java ME), Symbian, Binary Runtime environment forWireless (BREW), Microsoft .NET Compact Framework,

Objective C, and Python are available for developing mobile

applications.


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Introduction to Mobile Application Development (Contd.)

Java ME:

Is also known as Java 2 Micro Edition (J2ME).

Is a Java-based platform developed by Sun Microsystems.

Provides an environment for developing applications for

wireless mobile devices and embedded devices.Includes flexible User Interfaces (UIs), a strong security model,

and built-in network protocols that can be used to create rich

and powerful wireless applications for mobile devices.


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Introducing Java ME

Sun Microsystems have released several versions of Java,

and they have maintained a consistent architecture across

these versions.

The three Java editions are:

Java Standard Edition (Java SE)Java Enterprise Edition (Java EE)

Java ME


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Introducing Java ME (Contd.)

Java ME:

Shares some classes with Java SE and Java EE.

Contains its own classes, called Profile Application Program

Interfaces (Profile APIs) that are not a part of Java SE and

Java EE APIs.The following figure shows the library sets of the three Java

editions in terms of a set diagram.


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Understanding the Java ME Architecture

The micro world

includes a wide range

of devices with

different capabilities.

Is it possible to

create a single

software product tosuit all of them?


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Understanding the Java ME Architecture (Contd.)

No, it is not possible to

create a single software

product to suit all of them.


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Java ME is designed as a

collection of specifications that

define a set of platforms.

Each of these platforms is

suitable for a subset of the

collection of devices that fall

within its scope.

This subset for a particular

collection of devices is defined

by a configuration and one or

more profiles.

The configuration and profile,

together, provide APIs to

develop applications for this

collection of devices.


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Describing Java ME configurations:

A configuration is a specification that defines a software

environment for a range of devices defined by a set of

characteristics that the specification relies upon.

The characteristics that are defined for the range of devicesmay be the:

Type and amount of memory available.

Type of processor and its speed.

Type of network connections available to the devices.

A configuration:

Represents the minimum platform for the devices.Provides the basic set of classes and libraries required to support

devices with similar memory and processing requirements.


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The Java ME architecture is based on two types of

configurations:

Connected Device Configuration (CDC)

Connected Limited Device Configuration (CLDC)

CLDC defines a basic set of classes and libraries forresource-restricted devices such as mobile phones and

PDAs.

CDC defines a basic set of classes and libraries for devices

such as set-top boxes.


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Describing Java ME Profiles:

A profile provides additional classes for a certain range of

devices within the framework of a chosen configuration.

The classes provided by the profile are suitable to a particular

family of devices within a given configuration.Profiles help in managing device-specific features, such as

creating Graphical User Interfaces (GUIs), and managing data

storage and network connections.

The Mobile Information Device Profile (MIDP) is a

CLDC-based profile that defines class libraries to develop

applications for network-connectable mobile devices.The Foundation profile is a CDC-based profile.


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Describing the Java ME Architecture:

Java ME uses a layered architecture, which defines the

following major categories of components:

Configuration layer: This layer includes a Kilobytes Virtual

Machine (KVM) or C Virtual Machine (CVM), which is similar to the

Java Virtual Machine (JVM).

Profile layer: This layer adds classes to the chosen configuration

to support device specific functionalities.

The Java ME layered architecture also includes an additional

layer of optional packages.

Optional packages:Are always used in combination with a configuration or a profile.

Add standard APIs to develop applications that provide

functionality, such as ability to send messages and play audio

content.


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Example for optional package:

Wireless Messaging API (WMA) is an optional package that can

be used to develop applications for sending and receiving

messages through mobile devices having Short Messaging

Service (SMS) capabilities.

The WMA package can be used with CLDC and MIDP, or withsome other configuration and profile.


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The following figure depicts the layered architecture of Java

ME for the CLDC configuration.


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Steve is a mobile application developer with Info Super

Corp. He is assigned the task to develop a game application

for mobile devices. Steve needs to add GUI to the game

application. Which layer of Java ME architecture can

provide him the class libraries to perform the required task?

Just a Minute

Solution:

Profile layer


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Features of Java ME

The features of the Java ME platform are:

Security

Portability

Dynamic content delivery

Enhanced UI and Interactive contentOffline access

Compatibility with Java SE and Java EE platforms


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In this session, you learned that:

Java ME provides an environment for developing applications

for wireless mobile devices, such as mobile phones and PDAs,

and embedded devices, such as set-top boxes and printers.

The Java ME platform includes flexible UIs, a strong securitymodel, and built-in network protocols that can be used to

create rich and powerful wireless applications for mobile

devices.

The Java ME architecture is designed for small devices that

have common hardware and software characteristics. Some of

these characteristics are:Limited memory

Limited processing

Limited display

Limited input methods

Limited networking capabilities

Summary


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A configuration and a profile, together, provide APIs to develop

mobile applications.

A configuration is a specification that defines the software

environment for mobile devices.

The two types of configurations in Java ME are CDC and

CLDC.

The MIDP is a commonly used Java ME profile for CLDC.

Java ME uses a layered architecture, which defines the

following major categories of components:

Configuration layer

Profile layerThe Java ME layered architecture also includes an additional

layer of optional packages, which is always used in

combination with a configuration or a profile.

Summary (Contd.)


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The features of the Java ME platform are:

Profile layer

Security

Portability

Dynamic content delivery

Enhanced UI and Interactive content

Offline access

Compatibility with Java SE and Java EE platforms

Summary (Contd.)

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