Developing an Application with J2ME Technology
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Transcript of Developing an Application with J2ME Technology
Developing an Developing an Application with J2ME Application with J2ME
TechnologyTechnology
Scott Palmer, Nat Panchee, Judy Sullivan,
Karen Thabet, Sten Westgard
Java -Java -“One size does not fit all”“One size does not fit all”
Java Technology - EditionsJava Technology - Editions
Memory footprint decreases
J2ME - CharacteristicsJ2ME - Characteristics
J2ME maintains qualities of Java Technology
Consistency across products
Portability of code
J2ME - CharacteristicsJ2ME - Characteristics
Run anywhere, anytime and on any device
Safe network delivery
Upward scalability with J2SE and J2EE technology
OOP base language
What is a Configuration?What is a Configuration?
Specifies Java Programming language features supported
Specifies the JVM features supported
Specifies the basic Java libraries and APIs supported
J2ME ConfigurationsJ2ME Configurations
Connected Device Configuration (CDC)Connected Limited Device Configuration
(CLDC)Purpose:
– CDC – High end consumer devices– CDLC – Low end consumer devices
Java2 Micro Edition - Java2 Micro Edition - ArchitectureArchitecture
CDCCDC
32 bit processor >.5MB (ROM+RAM) JVM support High bandwidth network connectivity Devices include:
– Communicators– Next Generation Smart Phones– Home Appliances– Car Navigation Systems
CLDCCLDC
16-32 bit processor >160-512kB (ROM+RAM) KVM support Limited power/battery, network, GUI, Java class
libraries Devices include:
– Cell phones– Personal Digital Assistants– Pagers
CLDC Expert GroupCLDC Expert Group
America Online Bull Ericsson Fujitsu Matsushita Mitsubishi Motorola Nokia NTT DoCoMo
Oracle Palm Computing RIM Samsung Sharp Siemens Sony SunMicrosystems Symbian
CLDC PackagesCLDC Packages
CLDC packages:– java.lang– java.io– java.util– javax.microedition.io
CLDC CLDC
CLDC limitations:– No Floating-point Support– No Finalization– Error Handling Limitations– Limited Internationalization Support
MIDP – MIDP – Mobile Information Device ProfileMobile Information Device Profile
MIDP + CLDC = Part of J2ME Runtime Environment
MIDP addresses:– User Interface– Persistent storage– Networking– Application model
MIDP PackagesMIDP Packages
MIDP Packages:
– javax.micoredition.io– javax.microedition.midlet– javax.microedition.lcdui– javax.microedition.rms
What is a MIDlet?What is a MIDlet?
MIDP Application = MIDlet
MIDlet is similar to applet.
MIDlet Structure:– startApp()– pauseApp()– destroyApp(boolean unconditional)
MIDlet’s Life CycleMIDlet’s Life Cycle
destroyApp( )
PausedPaused
pauseApp( )
ActiveActive
DestroyedDestroyed
destroyApp( )
startApp( )
Hello MidletHello Midletimport javax.microedition.midlet.*;import javax.microedition.lcdui.*;
public class HelloMidlet extends MIDlet{ private Display display; TextBox box = null;
public HelloMidlet() { }
public void startApp() { display = display.getDisplay(this); box = new TextBox("Midlet Example", "Hello CS616", 20, 0); display.setCurrent(box); }
public void pauseApp() { }
public void destroyApp(boolean unconditional) { }}
Hello MidletHello Midlet
J2ME Wireless ToolkitJ2ME Wireless Toolkit
Developer OpportunitiesDeveloper Opportunities
Mobile Internet servicesValue added servicesBusiness to business apps
A Wireless “Safe Home”A Wireless “Safe Home”
Java Enabled Device FutureJava Enabled Device Future
“In 2002, Nokia will deliver more than 50 million Java enable phones; more than 100 million deliveries by end of 2003.”
Pekka Ala-Pietila,Nokia President, JavaOne, 2001