Java Platform, Micro Edition or Java ME is a

computing platform A computing platform or digital platform is an environment in which a piece of software is executed. It may be the hardware or the operating system (OS), even a web browser and associated application programming interfaces, or other underlying s ...

for development and deployment of portable code for embedded and mobile devices (micro-controllers, sensors, gateways, mobile phones, personal digital assistants, TV set-top boxes, printers). Java ME was formerly known as Java 2 Platform, Micro Edition or J2ME. As of December 22, 2006, the Java ME source code is licensed under the GNU General Public License, and is released under the project name phoneME. The platform uses the object-oriented Java programming language. It is part of the Java software-platform family. Java ME was designed by

Sun Microsystems Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the ...

, acquired by

Oracle Corporation Oracle Corporation is an American multinational computer technology corporation headquartered in Austin, Texas. In 2020, Oracle was the third-largest software company in the world by revenue and market capitalization. The company sells da ...

in 2010; the platform replaced a similar technology,

PersonalJava PersonalJava was a Java edition for mobile and embedded systems based on Java 1.1.8. It has been superseded by the CDC's Personal Profile Personal may refer to: Aspects of persons' respective individualities * Privacy * Personality * Person ...

. Originally developed under the Java Community Process as JSR 68, the different flavors of Java ME have evolved in separate JSRs. Oracle provides a reference implementation of the specification, but 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. As of 2008, all Java ME platforms are currently restricted to

JRE The Joe Rogan Experience (JRE) is a podcast hosted by American comedian and presenter Joe Rogan. JRE can also mean: *Java Runtime Environment *The Joe Rogan Experience *JR East, see East Japan Railway Company The is a major passenger railway ...

1.3 features and use that version of the class file format (internally known as version 47.0). Should Oracle ever declare a new round of Java ME configuration versions that support the later class file formats and language features, such as those corresponding to JRE 1.5 or 1.6 (notably,

generics Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

), it will entail extra work on the part of all platform vendors to update their JREs. 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. Profiles are subsets of ''configurations'', of which there are currently two: the Connected Limited Device Configuration (CLDC) and the Connected Device Configuration (CDC). There are more than 2.1 billion Java ME enabled mobile phones and PDAs. It was popular in sub-$200 devices such as Nokia's Series 40. It was also used on the Bada operating system and on

Symbian Symbian is a discontinued mobile operating system A mobile operating system is an operating system for mobile phones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typic ...

OS along with native software. Users of Windows CE, Windows Mobile, Maemo, MeeGo and

Android Android may refer to: Science and technology * Android (robot), a humanoid robot or synthetic organism designed to imitate a human * Android (operating system), Google's mobile operating system ** Bugdroid, a Google mascot sometimes referred to ...

can download Java ME for their respective environments ("proof-of-concept" for Android).

Connected Limited Device Configuration

The Connected Limited Device Configuration (CLDC) contains a strict subset of the Java-class libraries, and is the minimum amount needed for a

Java virtual machine A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes ...

to operate. CLDC is basically used for classifying myriad devices into a fixed configuration. A configuration provides the most basic set of libraries and virtual-machine features that must be present in each implementation of a J2ME environment. When coupled with one or more profiles, the Connected Limited Device Configuration gives developers a solid Java platform for creating applications for consumer and embedded devices. The configuration is designed for devices with 160KB to 512KB total memory, which has a minimum of 160KB of ROM and 32KB of RAM available for the Java platform.

Mobile Information Device Profile

Designed for mobile phones, the Mobile Information Device Profile includes a

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

, and a data storage 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. However, many cellphones can run only those MIDlets that have been approved by the carrier, especially in North America. ''JSR 271: Mobile Information Device Profile 3'' (Final release on Dec 9, 2009) specified the 3rd generation Mobile Information Device Profile (MIDP3), expanding upon the functionality in all areas as well as improving interoperability across devices. A key design goal of MIDP3 is backward compatibility with MIDP2 content.

Information Module Profile

The Information Module Profile (IMP) is a 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.

Connected Device Configuration

The Connected Device Configuration is a subset of Java SE, containing almost all the libraries that are not GUI related. It is richer than CLDC.

Foundation Profile

The Foundation Profile is a Java ME Connected Device Configuration (CDC) profile. This profile is intended to be used by devices requiring a complete implementation of the Java virtual machine up to and including the entire Java Platform, Standard Edition API. Typical implementations will use some subset of that API set depending on the additional profiles supported. This specification was developed under the Java Community Process.

Personal Basis Profile

The Personal Basis Profile extends the Foundation Profile to include lightweight GUI support in the form of an AWT subset. This is the platform that BD-J is built upon.

Implementations

Sun provides a reference implementation of these configurations and profiles for MIDP and CDC. Starting with the JavaME 3.0 SDK, a NetBeans-based IDE will support them in a single IDE. In contrast to the numerous binary implementations of the Java Platform built by Sun for servers and workstations, Sun does not provide any binaries for the platforms of Java ME targets with the exception of an MIDP 1.0 JRE (JVM) for Palm OS. Sun provides no J2ME JRE for the

Microsoft Windows Mobile Windows Mobile is a discontinued family of mobile operating systems developed by Microsoft for smartphones and personal digital assistants. Its origin dated back to Windows CE in 1996, though Windows Mobile itself first appeared in 2000 as Pock ...

(Pocket PC) based devices, despite an open-letter campaign to Sun to release a rumored internal implementation of

known by the code name "Captain America". Third party implementations are widely used by Windows Mobile vendors. Operating systems targeting Java ME have been implemented by DoCoMo in the form of

DoJa DoJa profile is a Java application environment specification for DoCoMo's i-mode mobile phone. DoJa is based on the Java ME CLDC API that is defined in the Java Community Process (JCP). DoJa is a profile defined by NTT DoCoMo to provide communi ...

, and by SavaJe as SavaJe OS. The latter company was purchased by Sun in April 2007 and now forms the basis of Sun's

JavaFX Mobile JavaFX is a software platform for creating and delivering desktop applications, as well as rich web applications that can run across a wide variety of devices. JavaFX has support for desktop computers and web browsers on Microsoft Windows, Lin ...

. The open-source

Mika VM Mika VM is an open-source implementation of the Java virtual machine specification, together with class libraries which implement the Connected Device Configuration of Java ME. Mika VM is based on Wonka VM, which was developed independently of a ...

aims to implement JavaME CDC/FP, but is not certified as such (certified implementations are required to charge royalties, which is impractical for an open-source project). Consequently, devices which use this implementation are not allowed to claim JavaME CDC compatibility. The Linux-based Android operating system uses a proprietary version of Java that is similar in intent, but very different in many ways from Java Me.Mobile application development: Android compared to J2ME
Feb 2013

JSRs (Java Specification Requests)

Foundation

Main extensions

Future

ESR

The ESR consortium is devoted to Standards for embedded Java. Especially cost effective Standards. Typical applications domains are industrial control, machine-to-machine, medical, e-metering,

home automation Home automation or domotics is building automation for a home, called a smart home or smart house. A home automation system will monitor and/or control home attributes such as lighting, climate, entertainment systems, and appliances. It m ...

, consumer, human-to-machine-interface, ...

References

;Notes
JSR 232: Mobile Operational Management
an advanced OSGi technology based platform for mobile computing
JSR 291: Dynamic Component Support for Java SE
symmetric programming model for Java SE to Java ME JSR 232

Bibliography

* * *

External links

Sun Developer Network, Java ME

Nokia's Developer Hub Java pages

Nokia S60 Java Runtime blogs

Sony Ericsson Developer World

Motorola Developer Network

J2ME Authoring Tool LMA Users Network

Samsung Mobile Developer's site

Sprint Application Developer's Website

Performance database of Java ME compatible devices

MicroEJ platforms for embedded systems

Book - Mobile Phone Programming using Java ME (J2ME)

Tutorial Master ng, J2ME
{{Mobile operating systems Computing platforms Platform, Micro Edition Platform, Micro Edition