Java 2 Micro Edition (J2ME)

Computer technology is showing up everywhere and catching up every one in the form of wireless (mobile) and wired (stationary) network-based products that are for the comforts and convenience of consumers in this fast-moving world. The world of wireless includes small battery-operated, hand-held devices such as cell phones, two-way pagers, personal organizers, screen phones, point-of-sale (POS) terminals, and smart card readers. There seems to be a number of valuable and exciting applications for these special-purpose, limited-function, and network-based information appliances in the days to come, for example, for accessing and checking security, audio and video systems and appliances in home from remote places, access the Internet for the latest stock quotes, make instant reservations, buy tickets for entertainment, download information and view flashing news, doing online commercial activities etc. This list is quiet expanding dramatically according to the advanced requirements of the consumers.

Microprocessor-based consumer products such as televisions, cars, phones, air conditioners, coffee makers, portable digital gadgets, and personal organizers are referred to as embedded devices because the small computers inside them have a very limited set of operations unlike personal computers.

Sun Microsystems with the assistance from others has developed a number of API specifications and a Java virtual machine specification called as Java 2 Micro Edition (J2ME) targeting the various embedded devices. J2ME defines an appropriate set of class libraries and specific virtual machine technology for every sort of embedded devices in this planet.

Java-based embedded technologies let developers to design applications that can run on any target device that supports a compatible implementation, that is, these help to develop device-independent software applications. These technologies are based on configurations and profiles while non-Java technologies for the same purpose are based on different methodologies. A configuration defines the minimum set of class libraries available for a range of devices. A profile defines the set of APIs available for a particular family of devices. Each family of devices has its own profile that represents a particular vertical market within a given configuration. Here comes the list of Java-based configurations and profiles for different embedded devices and a brief explanation follows.

Apart from these, there are other Java-based technologies for the ever-growing consumer and embedded devices markets. They are Jini, Java Card and Java Embedded Server technologies.

J2ME CLDC, J2ME MIDP profile, J2ME PDA profiles are mainly used for writing applications using personal computers or workstations to run in wireless (mobile) hand-held devices while J2ME CDC, J2ME Foundation profile, and J2ME Personal profiles are for writing applications to run in stationary hand-held devices.

Digital Interactive TV enhances the e-mail, programming, and pay-per-view features available through standard digital television by providing interactive capabilities. This is being possible by using a standard set-top box to initiate transactions with our bank, hardware store, or video store etc. Java TV API technology is being used to write such kinds of interactive applications for set-top boxes. Java Embedded Server technology is being used for connecting the digital TV to the Internet and other home appliances.

Today it is possible to use global positioning satellite software in our automobile to help us find our way to our destination. Soon one can use satellite communications from automobiles to get Digital Interactive TV programming and Internet access. This helps to initiate e-commerce transactions or download entertainment software, service updates, email, address information, and calendar appointments. The following Java-based technologies make them possible:

The networked homes of tomorrow will have a box for networking appliances within the home and connecting them to the Internet. This type of network would enable washing machines to download new and advanced washing programs dynamically, electronic toys to download updated game programs, and give us the ability to turn off the oven, iron, or lights after we have left for a trip. The Sun Microsystems has come out with a couple of technologies to accomplish the networked homes. They are Java Embedded Server technology for getting connected to the Internet and downloading various innovative services available to the home networked appliances. The second and flourishing one is Jini Connection technology, which is being used for creating a community of networked devices in the home or office.

Here is an overview of Jini technology.

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