Mobile Application Development

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Mobile Application Development

Deployment

Development Process and Portability

Christoph Denzler

University of Applied Sciences Northwestern Switzerland Institute for Mobile and Distributed Systems

Learning Target

You

know of what steps the deployment process

consists for a MIDlet application

are aware of the fragmentation problems in the

J2ME market

can apply some strategies to this problem

know how to develop and deploy the same

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Deployment IMVS, Ch. Denzler 3

Development & Deployment

Compiling Packaging Deploying

Porting

Device Fragmentation Design for Portability

Overview : Development & Deployment

Editing javac preverify jar obfuscate copy on Webserver download .jad download .jar install & verify run (KVM) enter URL Cell Phone Service Provider Internet Development _Installation

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Compiling

javac -bootclasspath

../../lib/cldcapi10.jar; ../../lib/midpapi20.jar

-d tmpclasses -source 1.3 -target 1.1

src/hello/HelloMIDlet.java

bootclasspath loads requested libraries source indicates language compatibility target indicates byte code compatibility d destination folder is tmpfolder

Preverify

preverify -classpath ../../lib/cldcapi10.jar;

../../lib/midpapi20.jar -d classes tmpclasses

classpath lists necessary libraries

-d destination folder

Verifies byte code.

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jar cfm bin/Hello.jar bin/MANIFEST.MF

-C classes .

cfm: creates a jarfile with the given manifest. Note m

and f must be in the same order that jarfile and manifest appear

-C: directory with the compiled and preverified

classes

Obfuscation

java -jar ../../bin/proguard.jar

-libraryjars ../../lib/cldcapi10.jar;

../../lib/midpapi20.jar

-injars bin/Hello.jar -outjar /deploy/Hello.jar

-keep "public class * extends

javax.microedition.midlet.MIDlet "

ofuscates all injars and produces an outjar does not obfuscate terms in -keep

Minimize memory footprint by

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Installation

OTA (over the air)

.jad file is downloaded and its content will be

presented to the user.

User decides to proceed.

.jar file is downloaded and application will be

installed.

Direct transfer from PC (usually only Windows)

Either wireless (Bluetooth, IrDA)

USB cable

Development Process & Tools

1. Develop the source code files.

Any texteditor

2. Compile the source code files into bytecode classes.

Standard Java Compiler (javac)

3. Pre-verify the bytecode classes (Off-Device Pre-verification) midlet classes must be verified prior to distribution to guarantee that

they don´t perform any illegal operations.

Reason: limitations of the virtual machine used in mobile devices

J2ME toolkit (WTK, JME SDK)

4. Package the bytecode classes into a Jar-file with any additional resources and a manifest file.

Java archive (jar) tool

5. Develop a Java Application Descriptor file (Jad-file) to accompany the Jar-file.

Generated and/or using texteditor

6. Test and debug the midlet.

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JAR Manifest

MIDlet-Name: Hello World MIDlet-Version: 1.0.0 MIDlet-Vendor: LOGIQUEST

MIDlet-Description: Hello World Demo MIDlet-Icon: img/hello.png

MIDlet-Data-Size: 0

MIDlet-1: Hello, img/hello.png, hello.HelloWorld

MicroEdition-Profile: MDIP-1.0 MicroEdition-Configuration: CLDC-1.0

Java Application Descriptor (JAD) MIDlet-Name: Hello World

MIDlet-Version: 1.0.0 MIDlet-Vendor: LOGIQUEST

MIDlet-Description: Hello World Demo MIDlet-Icon: img/hello.png

MIDlet-Data-Size: 0 MIDlet-Jar-Size: 1251 MIDlet-Jar-URL: hello.jar

User-defined entries can be read with the MIDlet method String getAppProperty(String key)

JAD file properties

_{JAD File Content}

MIDlet-Name MIDlet-Version MIDlet-Vendor

MIDlet-<n> for each MIDlet MIDlet-Jar-URL

MIDlet-Jar-Size

_TheMIDlet-<n>property specifies the name of the MIDlet and an icon (for selecting the MIDlet to be run), and the name in the JAR file of the class which

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Packaging MIDlets

_{One or more MIDlets are packed in a “MIDlet Suite”:}

Java class files, other resources (images etc.) and a Manifest, in

a JAR file,

A Java Application Descriptor (JAD) file describing the MIDlets

(and largely repeating the Manifest), in the form of Java properties (key: valuepairs)

_{The JAD file allows the device’s application manager to}

decide whether the MIDlets can be executed on the device.

Porting and Testing Application

Porting and testing applications is very time

consuming since there are differences between

different phone models such as:

Screen size Memory Processor Bugs Operator problems Specification divergence

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_{Mobile device fragmentation limits mobile application}

adoption and thereby Carriers’ ARPU (average revenue per user) growth

Different hardware Different API support

Different standards: MIDP, DoJa, BlackBerry, etc. Different interpretations of standards

Device bugs

Example: Design problems

The mobile Java standard only allows limited

design of applications, unless every detail is

drawn by the application itself

Standard implementations do not allow to influence

the CI and look and feel of the application

Adapting designs to different environments or

customers is difficult

Design changes require changing the source code of

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Java ME: De-fragmentation

_{The problem}

More than 600 J2ME device types

It is expensive to develop, test and sign, deliver and maintain Ever increasing operational costs

Commercial "failure" of the J2ME platform

_{The solution:}

De-fragmentation

Possible due to increased capabilities of the devices Improved programming techniques