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 device A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physical ...

s (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 The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the Four Freedoms (Free software), four freedoms to run, study, share, and modify the software. The license was th ...

, and is released under the project name

phoneME In phonology and linguistics, a phoneme () is a unit of sound that can distinguish one word from another in a particular language. For example, in most dialects of English, with the notable exception of the West Midlands and the north-west o ...

. The platform uses the

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of pro ...

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

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 The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is ...

. Originally developed under the

Java Community Process The Java Community Process (JCP), established in 1998, is a formalized mechanism that allows interested parties to develop standard technical specifications for Java technology. Anyone can become a JCP Member by filling a form available at thJCP w ...

as JSR 68, the different flavors of Java ME have evolved in separate JSRs. Oracle provides a

reference implementation In the software development process, a reference implementation (or, less frequently, sample implementation or model implementation) is a program that implements all requirements from a corresponding specification. The reference implementation o ...

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 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), 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 Mobile Information Device Profile (MIDP) is a specification published for the use of Java on embedded devices such as mobile phones and PDAs. MIDP is part of the Java Platform, Micro Edition (Java ME) framework and sits on top of Connected Limit ...

aimed at mobile devices, such as cell phones, and the

Personal Profile Personal may refer to: Aspects of persons' respective individualities * Privacy * Personality * Personal, personal advertisement, variety of classified advertisement used to find romance or friendship Companies * Personal, Inc., a Washington, ...

aimed at consumer products and embedded devices like

set-top box A set-top box (STB), also colloquially known as a cable box and historically television decoder, is an information appliance device that generally contains a TV-tuner input and displays output to a television set and an external source of sign ...

es 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 Series 40, often shortened as S40, is a software platform and application user interface (UI) software on Nokia's broad range of mid-tier feature phones, as well as on some of the Vertu line of luxury phones. It was one of the world's most wi ...

. It was also used on the

Bada Bada (stylized as bada; Korean: ) is a discontinued mobile operating system developed by Samsung Electronics for devices such as mid- to high-end smartphones and tablet computers. The name is derived from " (bada)", meaning "ocean" or "sea" in ...

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 Embedded Compact, formerly Windows Embedded CE, Windows Powered and Windows CE, is an operating system subfamily developed by Microsoft as part of its Windows Embedded family of products. Unlike Windows Embedded Standard, which is base ...

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 ...

Maemo Maemo is a software platform originally developed by Nokia, now developed by the community, for smartphones and Internet tablets. The platform comprises both the Maemo operating system and SDK. Maemo played a key role in Nokia's strategy to com ...

MeeGo MeeGo is a discontinued Linux distribution hosted by the Linux Foundation, using source code from the operating systems Moblin (produced by Intel) and Maemo (produced by Nokia). Primarily targeted at mobile devices and information appliances ...

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

Connected Limited Device Configuration

The

Connected Limited Device Configuration The Connected Limited Device Configuration (CLDC) is a specification of a framework for Java ME applications describing the basic set of libraries and virtual-machine features that must be present in an implementation. The CLDC is combined with one ...

(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

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 An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

. Applications written for this profile are called

MIDlet A MIDlet is an application that uses the Mobile Information Device Profile (MIDP) of the Connected Limited Device Configuration (CLDC) for the Java ME environment. Typical applications include games running on mobile devices and cell phones which ...

s. Almost all new cell phones come with a MIDP implementation, and it is now the

de facto ''De facto'' ( ; , "in fact") describes practices that exist in reality, whether or not they are officially recognized by laws or other formal norms. It is commonly used to refer to what happens in practice, in contrast with ''de jure'' ("by la ...

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 stands for the ''Information Module Profile''. It is a specification put out by Sun Microsystems for the use of Java on embedded devices with very limited displays. It is a subset of the Mobile Information Device Profile. IMP is part of the Jav ...

(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 Siemens Mobile was a German mobile phone manufacturer and a division of Siemens AG. Siemens sold Siemens Mobile to the Taiwan-based BenQ in 2005, subsequently becoming BenQ-Siemens and succeeded by Gigaset. The last Siemens-branded mobile phones, ...

and

Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational corporation, multinational telecommunications industry, telecommunications, technology company, information technology, and consumer electronics corporatio ...

as JSR-195, IMP 1.0 is a strict subset of

MIDP Mobile Information Device Profile (MIDP) is a specification published for the use of Java on embedded devices such as mobile phones and PDAs. MIDP is part of the Java Platform, Micro Edition (Java ME) framework and sits on top of Connected Limi ...

1.0 except that it doesn't include

user interface In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine f ...

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

2.0, leveraging

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 The Connected Device Configuration (CDC) is a specification of a framework for Java ME applications describing the basic set of libraries and virtual-machine features that must be present in an implementation. The CDC is combined with one or more pr ...

is a subset of

Java SE Java Platform, Standard Edition (Java SE) is a computing platform for development and deployment of portable code for desktop and server environments. Java SE was formerly known as Java 2 Platform, Standard Edition (J2SE). The platform uses Ja ...

, 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 BD-J, or Blu-ray Disc Java, is a specification supporting Java ME (specifically the Personal Basis Profile of the Connected Device Configuration or CDC) Xlets for advanced content on Blu-ray Disc and the Packaged Media profile of Globally Execut ...

is built upon.

Implementations

Sun provides a

of these configurations and profiles for MIDP and CDC. Starting with the JavaME 3.0 SDK, a

NetBeans NetBeans is an integrated development environment (IDE) for Java (programming language), Java. NetBeans allows applications to be developed from a set of modular software components called ''modules''. NetBeans runs on Microsoft Windows, Windows, ...

-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, Linux ...

. 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, 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