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'''Java Platform, Micro Edition''' or '''Java ME''' (formerly referred to as J2ME), is a runtime and collection of [[Java programming language|Java]] [[Application Programming Interface|API]]s for the development of software for resource constrained devices such as [[Personal Digital Assistant|PDA]]s, [[cell phone]]s and other consumer appliances. |
'''Java Platform, Micro Edition''' or '''Java ME''' (formerly referred to as J2ME), is a runtime and collection of [[Java programming language|Java]] [[Application Programming Interface|API]]s for the development of software for resource constrained devices such as [[Personal Digital Assistant|PDA]]s, [[cell phone]]s and other consumer appliances. |
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Revision as of 09:56, 21 February 2006
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Java Platform, Micro Edition or Java ME (formerly referred to as J2ME), is a runtime and collection of Java APIs for the development of software for resource constrained devices such as PDAs, cell phones and other consumer appliances.
Java ME was designed by Sun Microsystems and is a replacement for a similar technology PersonalJava.
Java ME has become a popular option for creating games for cell phones, as they can be emulated on a PC during the development stage and easily uploaded to the phone. This contrasts with the difficulty of developing, testing, and loading games for other special gaming platforms such as those made by Nintendo, Sony, and others, as expensive system-specific hardware and kits are required.
Sun Microsystems has tended not to provide free binary implementations of its Java ME runtime environment for mobile devices, rather relying on third parties to provide their own, in stark contrast to the numerous binary implementations it provides for the full Java platform standard on server and workstation machines. One of the notable omissions is for Microsoft Windows Mobile (Pocket PC) based devices, despite an open letter campaign to Sun to release a rumoured complete project "Captain America" which is such an implementation.
Configurations and Profiles
Java ME devices implement a profile. The most common of these are the Mobile Information Device Profile aimed at mobile devices, such as cell phones, and the Personal Profile aimed at consumer products and embedded devices like Set-top boxes and PDAs.
A profile is a superset of a configuration, of which there are currently two: Connected Limited Device Configuration and Connected Device Configuration.
Connected Limited Device Configuration
The CLDC contains a strict subset of the Java class libraries, and is the minimal needed for a Java virtual machine to operate. CLDC is basically used to classify the myriad of devices into a fixed configuration.
Mobile Information Device Profile
Designed for cell phones, MIDP boasts an LCD-oriented GUI API, and MIDP 2.0 includes a basic 2D gaming API. Applications written for this profile are called MIDlets. Almost all new cell phones come with a MIDP implementation, and it is now the de facto standard for downloadable cell phone games.
Information Module Profile
The Information Module Profile (IMP) is a Java ME profile for embedded, "headless" devices such as vending machines, industrial embedded applications, security systems, and similar devices with either simple or no display and with some limited network connectivity.
Originally introduced by Siemens Mobile and Nokia as JSR-195, IMP 1.0 is a strict subset of MIDP 1.0 except that it doesn't include user interface
APIs — in other words, it doesn't include support for the Java package javax.microedition.lcdui
. JSR-228, also known as IMP-NG, is IMP's next generation that is based on MIDP 2.0, leveraging MIDP 2.0's new security and networking types and APIs, and other APIs such as PushRegistry
and platformRequest()
, but again it doesn't include UI APIs, nor the game API.
IMP applications are called IMlets, but in reality they are MIDlets. They subclass MIDlet, and follow the same packaging, deployment, security and life-cycle as MIDlets.
Connected Device Configuration
CDC is a smaller subset of Java SE, containing almost all the libraries that are not GUI related.
Foundation Profile
A headless version of Java SE.
Personal Basis Profile
Extends the Foundation Profile to include lightweight GUI support in the form of an AWT subset.
Personal Profile
This extension of Personal Basis Profile includes a more comprehensive AWT subset and adds applet support.
External links
- The Source for Java ME Developers (Java ME Homepage)
- J2ME.org Forum
- developer.sprint.com Java ME Programming for Sprint and Nextel (Operator)
- SprintDevelopers.com Java ME Programming for SprintPCS
- www.motocoder.com Java ME Programming for Motorola PCS phones
- idendev.com Java ME Programming for Motorola iDEN phones
- forum.nokia.com Java ME Programming for Nokia phones
- www.vipera.com Java ME Programming for Vipera mobile network
- developer.samsungmobile.com Java ME Programming for Samsung phones
- www.sony-ericsson.com/developer Java ME Programming for Sony-Ericsson phones
- Micro Developer Network Resource site for Java ME Developers with more industry related info.
- J2ME Polish Open Source Development Tool for Java ME
- Java ME Open Source Software Java ME Open Source Software Directory
- JavaMEDeveloper.com Resources for Java ME Developers
- openwap.org Open Source Midlets News and Software
- Java Tech Talk All about Java Technology. Every thing between try {} catch.
- An Example Midlet (MIDP1.0+). Thousands of Midlets are now available. This is an example of an established free one.
- Palowireless Java Resource Center J2ME Articles, news and resources