Java Platform, Micro Edition
Java Platform, Micro Edition , abbreviated to Java ME [ ˈdʒɑːvə ˌɛmˈiː ], formerly also known as Java Platform 2, Micro Edition or J2ME for short , is an implementation of the Java programming language for embedded consumer products such as mobile phones or PDAs . It is defined in Java Specification Requests 30 and 37.
The configurations and profiles form the basis of Java ME .
With J2ME it is therefore possible to run applications on mobile devices, regardless of manufacturer / model / operating system, since these applications are run independently of the JavaRuntime.
Configurations
The configurations provide various libraries and a virtual machine . Such a configuration can be the Connected Device Configuration (CDC) or, for mobile devices, the Connected Limited Device Configuration ( CLDC ) . Only these two configurations are currently available. A very strong increase is observed with the CLDC, as almost every current cell phone uses this configuration in combination with the Mobile Information Device Profile .
Profiles
Profiles are the APIs that are available for a configuration. The Mobile Information Device Profile ( MIDP ) exists especially for cell phones . Java applications that were developed on the basis of MIDP are also called MIDlet for short . This could be, for example, the "Java games for cell phones" that have been advertised frequently since 2002/2003. Another profile is the Information Module Profile (IMP) , which is a subset of the MIDP and is intended for machine-to-machine communication. A drinks machine can be seen as an example of its field of application, which wants to be filled and then reports somewhere via this profile.
Meanwhile there is also MIDP2.0. This version has been expanded to meet the needs of game developers in particular. Another version of Java ME is DoJa , the Java version of the Japanese mobile phone provider NTT DOCOMO , which is used on i-mode handsets.
Extensions
The simpler configurations are not enough for many purposes, as they do not provide access to the internal functions of a device. That is why there are many extensions that enable the address book of a mobile phone (JSR-75) or the built-in Bluetooth functionality (Java BlueTooth Wireless Technology: JSR-82 / JABWT) to be used. The necessary extensions are carried out as part of the Java Community Process (JCP). Well-known manufacturers such as Nokia , Siemens and IBM make change requests and then take the lead in the implementation. For example, IBM and PalmSource are leaders in change request JSR-75 "PDA Optional Packages for the J2ME (TM) Platform" .
history
The source code of Sun's reference implementation of Java ME has been disclosed since December 22, 2006 and is being distributed as free software under the terms of the GNU General Public License (GPL) as part of a project called phoneME .
Sun announced to CNet in October 2007 that it would give up the Java ME platform in favor of Java Standard Edition . The reason for this is that the devices for which Java ME was once created became more and more powerful. The changeover should not happen in one fell swoop, but will take place over the next few years.
Other Java platforms
literature
- Michael Pfeiffer: Java Micro Edition. Develop mobile applications with MIDP 2.0. Galileo Computing, Bonn 2007, ISBN 978-3-89842-505-6 .
Web links
- http://www.oracle.com/technetwork/java/javame/index.html Oracle Technology Network: Java ME Landing Page
- http://j2me-device-db.sourceforge.net/ - J2ME Device DB facilitates multi-device development and deployment with its database and tools
- http://www.j2mepolish.org/ - J2ME Polish is a development tool for creating Java ME applications
- To designate the individual Java platforms
- Extensive database with information on the JavaME capabilities of mobile telecommunication devices
- Diploma thesis on J2ME & Bluetooth