J2ME

Code-Division Multiple Access (CDMA) is a cellular technology widely used in North America. There are currently three CDMA standards: CDMA One, CDMA2000 and W-CDMA. CDMA technology uses UHF 800Mhz-1.9Ghz frequencies and bandwidth ranges from 115Kbs to 2Mbps.

The Connected Device Configuration (CDC) is a specification for a J2ME configuration. Conceptually, CDC deals with devices with more memory and processing power than CLDC; it is for devices with an always-on network connection and a minimum of 2 MB of memory available for the Java system.

Advanced Mobile Phone Service (AMPS) is a first-generation analog, circuit-switched cellular phone network. Originally operating in the 800 MHz band, service was later expanded to include transmissions in the 1900 MHz band, the VHF range in which most wireless carriers operate. Because AMPS uses analog signals, it cannot transmit digital signals and cannot transport data packets without assistance from newer technologies such as TDMA and CDMA.

An Application Programming Interface (API) is a set of classes that you can use in your own application. Sometimes called libraries or modules, APIs enable you to write an application without reinventing common pieces of code. For example, a networking API is something your application can use to make network connections, without your ever having to understand the underlying code.

The J2ME Wireless Toolkit is a set of tools that provides developers with an emulation environment, documentation and examples for developing Java applications for small devices. The J2ME WTK is based on the Connected Limited Device Configuration (CLDC) and Mobile Information Device Profile (MIDP) reference implementations, and can be tightly integrated with Forte for Java

802.11 is a group of specifications for wireless networks developed by the Institute of Electrical and Electronics Engineers (IEEE). 802.11 uses the Ethernet protocol and CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing.

Java 2 Micro Edition is a group of specifications and technologies that pertain to Java on small devices. The J2ME moniker covers a wide range of devices, from pagers and mobile telephones through set-top boxes and car navigation systems. The J2ME world is divided into configurations and profiles, specifications that describe a Java environment for a specific class of device.

Personal Communications Service (PCS) is a suite of second-generation, digitally modulated mobile-communications interfaces that includes TDMA, CDMA, and GSM. PCS serves as an umbrella term for second-generation wireless technologies operating in the 1900MHz range

Over The Air (OTA) refers to any wireless networking technology.

An optional package is a set of J2ME APIs providing services in a specific area, such as database access or multimedia. Unlike a profile, it does not define a complete application environment, but rather is used in conjunction with a configuration or a profile. It extends the runtime environment to support device capabilities that are not universal enough to be defined as part of a profile or that need to be shared by different profiles. J2ME RMI and the Mobile Media RMI are examples of optional packages.

Obfuscation is a technique used to complicate code. Obfuscation makes code harder to understand when it is de-compiled, but it typically has no affect on the functionality of the code. Obfuscation programs can be used to protect Java programs by making them harder to reverse-engineer.

Modulation is the method by which a high-frequency digital signal is grafted onto a lower-frequency analog wave, so that digital packets are able to ride piggyback on the analog airwave.

A Mobile Switching Center (MSC) is a unit within a cellular phone network that automatically coordinates and switches calls in a given cell. It monitors each caller's signal strength, and when a signal begins to fade, it hands off the call to another MSC that's better positioned to manage the call.

Mobitex is a packet-switched, narrowband PCS network, designed for wide-area wireless data communications. It was developed in 1984 by Eritel, an Ericsson subsidiary, a nd there are now over 30 Mobitex networks in operation worldwide.

The Next Generation MIDP specification is currently under development by the Java Community Process. Planned improvements include XML parsing and cryptographic support.

The Mobile Information Device Profile (MIDP) is a specification for a J2ME profile. It is layered on top of CLDC and adds APIs for application life cycle, user interface, networking, and persistent storage.

MIDlets are packaged and distributed as MIDlet suites. A MIDlet suite can contain one or more MIDlets. The MIDlet suite consists of two files, an application descriptor file with a .jad extension and an archive file with a .jar file. The descriptor lists the archive file name, the names and class names for each MIDlet in the suite, and other information. The archive file contains the MIDlet classes and resource files.

A MIDlet is an application written for MIDP. MIDlet applications are subclasses of the javax.microedition.midlet.MIDlet class that is defined by MIDP.

The Mobile Execution Environment (MExE) is a specification created by the 3GPP which details an applicatio n environment for next generation mobile devices. MExE consists of a variety of technologies including WAP, J2ME, CLDC and MIDP.

LCDUI is a shorthand way of referring to the MIDP user interface APIs, contained in the javax.microedition.lcdui package. Strictly speaking, LCDUI stands for Liquid Crystal Display User Interface. It's a user interface toolkit for small device screens which are commonly LCD screens.