Q: What is J2ME
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.
is J2ME WTK
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 theInstitute of Electrical and Electronics Engineers (IEEE). 802.11 uses
protocol and CSMA/CA (carrier sense multiple access
with collision avoidance) for path sharing.
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
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.
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
In J2ME, a configuration defines
the minimum Java runtime environment for a family of devices: the combination
of a Java virtual machine (either the standard J2SE virtual machine or a much
more limited version called the CLDC VM) and a core
set of APIs. CDC and CLDC are configurations. See
also profile, optional package.
The Compact Virtual Machine (CVM)
is an optimized Java virtual machine1 (JVM) that is used by the CDC.
A deck is a collection of one or more
WML cards that can be downloaded, to a mobile phone, as a single entity.
Enhanced Data GSM Environment (EDGE)
is a new, faster version of GSM. EDGE isdesigned to support transfer rates up to 384Kbps and enable the delivery
of video and other high-bandwidth applications. EDGE is the result of a joint
effort between TDMA operators, vendors and carriers and the GSM Alliance.
The European Telecommunications Standards
Institute (ETSI) is a non-profitorganization that establishes telecommunications standards for Europe.
(FDMA) is a mechanism for sharing a radio frequency band among multiple users
by dividing it into a number of smaller bands.
is Foundation Profile
The Foundation Profile is a J2ME
profile specification that builds on CDC. It adds additional classes and
interfaces to the CDC APIs but does not go so far as tospecify user interface APIs, persistent
storage, or application life cycle. Other J2ME profiles build on the
CDC/Foundation combination: for example, the Personal Profile and the RMI
Profile both build on the Foundation Profile.
is Generic Connection Framework
The Generic Connection Framework
(GCF) makes it easy for wireless devices to make network connections. It is
part of CLDC and CDC and resides in the javax.microedition.io package.
The General Packet Radio System (GPRS)
is the next generation of GSM. It will be the basis of 3G networks in Europe
The Global System for Mobile Communications
(GSM) is a wireless network system that is widely used in Europe, Asia, and
Australia. GSM is used at three different
frequencies: GSM900 and GSM1800 are used in Europe,
Asia, and Australia, while GSM1900 is deployed in North America and other parts
of the world.
The Home Location Register (HLR)
is a database for permanent storage of subscriber data and service profiles.
Sometimes called "Java for i-mode",
i-appli is a Java environment based on CLDC. It is used on handsets in NTT
DoCoMo's i-mode service. While i-appli is similar to
MIDP, it was developed before the MIDP specification
was finished and the two APIs are incompatible.
The Integrated Dispatch Enhanced
Network(iDEN) is a wireless network system developed by Motorola. Various
carriers support iDEN networks around the world: Nextel is one of the largest
carriers, with networks covering North and South America.
A standard used by Japanese wireless
devices to access cHTML (compact HTML) Web sites and display animated GIFs and
other multimedia content.
Third generation (3G) wireless networks
will offer faster data transfer rates than current networks. The first
generation of wireless (1G) was analog cellular. The second generation (2G) is
digital cellular, featuring integrated voice and data communications. So-called
2.5G networks offer incremental speed increases. 3G networks will offer
dramatically improved data transfer rates, enabling new wireless applications
such as streaming media.
The 3rd Generation Partnership Project
(3GPP) is a global collaboration between 6 partners: ARIB, CWTS, ETSI, T1, TTA,
and TTC. The group aims to develop a globally
mobile system based on GSM
is Java Card
The Java Card specification allows
Java technology to run on smart cards and other small devices. The Java Card
API is compatible with formal international standards,
such as, ISO7816, and industry-specific standards,
such as, Europay/Master Card/Visa (EMV).
The Java Community Process (JCP)
an open organization of international Java developers and licensees who develop
and revise Java technology specifications, reference implementations, and
technology compatibility kits through a formal
is JDBC for CDC/FP
The JDBC Optional Package for CDC/Foundation
Profile (JDBCOP for CDC/FP) is an API that enables mobile Java applications to
communicate with relational database servers using a subset of J2SE's Java
Database Connectivity. This optional package is a strict subset of JDBC 3.0
that excludes some of JDBC's advanced and server-oriented features, such as
pooled connections and array types. It's meant for use with the Foundation
Profile or its supersets.
JavaHQ is the Java platform control center on your
Palm OS device.
Java Specification Request (JSR) is
the actual description of proposed and final specifications for the Java
platform. JSRs are reviewed by the JCP and the public before a final release of
a specification is made.
KittyHawk is a set of APIs used by
LG Telecom on its IBook and p520 devices.KittyHawk is based on CLDC. It is conceptually similar to MIDP but the
two APIs are
KJava is an outdated term for J2ME.
It comes from an early package of Java software for PalmOS, released at the
2000 JavaOne show. The classes for that release were
packaged in the
kSOAP is a SOAP API suitable for the
J2ME, based on kXML.
The kXML project provides a small
footprint XML parser that can be used with J2ME.
The KVM is a compact Java virtual
machine (JVM) that is designed for small devices. It supports a subset of the
features of the JVM. For example, the KVM does not
support floating-point operations and object
finalization. The CLDC specifies use of the KVM. According to folklore, the 'K'
in KVM stands for kilobyte, signifying that the KVM runs in kilobytes of memory
as opposed to megabytes.
Q: What is LAN
A Local Area Network (LAN) is a group of devices
connected with variouscommunications
technologies in a small geographic area. Ethernet is the most widely-used LAN
technology. Communication on a LAN can either be with Peer-to-Peer
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.
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 andMIDP.
A MIDlet is an application written
for MIDP. MIDlet applications are subclasses of the
javax.microedition.midlet.MIDlet class that is defined by MIDP.
Q: What is MIDlet
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.
Q: What is MIDP
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, userinterface,
networking, and persistent storage.
Q: What is MIDP-NG
The Next Generation MIDP specification is currently
under development by the Java Community Process. Planned improvements include
XML parsing and cryptographic support.
Q: What is Mobitex
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.
Q: What is MSC
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
Q: What is
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.
Q: What is optional
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.
Q: What is
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.
Q: What is OTA
Over The Air (OTA) refers to any wireless networking
Q: What is PCS
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.
Q: What is PDAP
The Personal Digital Assistant Profile (PDAP) is a
J2ME profile specification designed for small platforms such as PalmOS devices.
You can think of PDAs as being larger than mobile phones but smaller than
set-top boxes. PDAP is built on top of CLDC and will specify user interface and
persistent storage APIs. PDAP is currently being developed using the Java
Community Process (JCP).
Q: What is PDC
Personal Digital Cellular (PDC) is a Japanese
standard for wireless communications.
Q: What is PDCP
Parallel and Distributed Computing Practices (PDCP)
are often used to describe computer systems that are spread over many devices
on a network (wired or wireless)
where many nodes process data simultaneously.
Q: What is
The Personal Profile is a J2ME profile specification.
Layered on the Foundation Profile and CDC, the Personal Profile will be the
next generation of PersonalJava
technology. The specification is currently in
development under the Java Community Process (JCP).
Q: What is
PersonalJava is a Java environment based on the Java
virtual machine1 (JVM) and a set of APIs similar to a JDK 1.1 environment. It
includes the Touchable Look and Feel (also called Truffle), a graphic toolkit
that is optimized for consumer devices with a touch sensitive screen.
PersonalJava will be included in J2ME in the upcoming Personal Profile, which
is built on CDC.
Q: What is PNG
Portable Network Graphics (PNG) is an image format
offering lossless compression and storage flexibility. The MIDP specification
requires implementations to recognize certain types of PNG images.
Q: What is POSE
Palm OS Emulator (POSE).
Q: What is PRC
Palm Resource Code (PRC) is the file format for Palm
Q: What is
Due to memory and processing power available on a
device, the verification process of classes are split into two processes. The
first process is the preverification
which is off-device and done using the preverify
tool. The second process is verification which is done on-device.
Q: What is profile
A profile is a set of APIs added to a configuration
to support specific uses of a mobile device. Along with its underlying
configuration, a profile defines acomplete, and usually self-contained, general-purpose application
Profiles often, but not always, define APIs for user
interface and persistence; the MIDP profile, based on the CLDC configuration,
fits this pattern. Profiles may be supersets or subsets of other profiles; the
Personal Basis Profile is a subset of the Personal Profile and a superset of
the Foundation Profile. See also configuration, optional package.
Q: What is
In telecommunications terms, provisioning means to
provide telecommunications services to a user. This includes providing all
necessary hardware, software, and wiring or transmission devices.
Q: What is PSTN
The public service telephone network (PSTN) is the
traditional, land-line based system for exchanging phone calls.
Q: What is RMI
Remote method invocation (RMI) is a feature of J2SE
that enables Java objects running in one virtual machine to invoke methods of
Java objects running in another virtual machine, seamlessly.
Q: What is RMI OP
The RMI Optional Package (RMI OP) is a subset of J2SE
1.3's RMI functionality used in CDC-based profiles that incorporate the
Foundation Profile, such as the Personal
Basis Profile and the Personal Profile. The RMIOP
cannot be used with CLDC-based profiles because they lack object serialization
and other important features found only in CDC-based profiles. RMIOP supports
most of the J2SE RMI functionality, including the Java Remote Method Protocol,
marshalled objects, distributed garbage collection, registry-based object
lookup, and network class loading, but not HTTP
tunneling or the Java 1.1 stub protocol.
Q: What is RMI
The RMI Profile is a J2ME profile specification
designed to support Java's Remote Method Invocation (RMI) distributed object
system. Devices implementing the RMI Profile will be able to interoperate via
RMI with other Java devices, including Java 2, Standard Edition. The RMI
Profile is based on the Foundation Profile, which in turn is based on CDC.
Q: What is RMS
The Record Management System (RMS) is a simple record-oriented
database that allows a MIDlet to persistently store information and retrieve it
later. Different MIDlets
can also use the RMS to share data.
Q: What is SIM
A Subscriber Identity Module (SIM) is a stripped-down
smart card containing information about the identity of a cell-phone
subscriber, and subscriber authentication and service information. Because the
SIM uniquely identifies the subscriber and is portable among handsets, the user
can move it from one kind of
phone to another, facilitating international roaming.
Q: What is T9
T9 is a text input method for mobile phones and other
small devices. It replaces the "multi-tap" input method by guessing
the word that you are trying to enter. T9 may be embedded in a device by the
manufacturer. Note that even if the device supports T9, the Java implementation
may or may not use it. Check yourdocumentation for details.
Q: What is TDMA
Time Division Multiple Access (TDMA) is a
second-generation modulation standard using bandwidth allocated in the 800 MHz,
900 MHz, and 1900MHz ranges.
Q: What is W-CDMA
Wideband Code-Division Multiple Access (W-CDMA), also
known as IMT-2000, is a 3rd generation wireless technology. Supports speeds up
to 384Kbps on a wide-area network, or 2Mbps locally.
Q: What is WDP
Wireless Datagram Protocol (WDP) works as the
transport layer of WAP. WDP processes datagrams from upper layers to formats
required by different physical datapaths, bearers, that may be for example GSM
SMS or CDMA Packet Data. WDP is adapted to
the bearers available in the device so upper layers
don't need to care about the physical level.
Q: What is WMA
The Wireless Messaging API (WMA) is a set of classes
for sending and receivingShort Message
Service messages. See also SMS.
Q: What is WML
The Wireless Markup Language (WML) is a simple
language used to create applications for small wireless devices like mobile
phones. WML is analogous to HTML in the World Wide Web.
Q: What is
language designed as part of the WAP standard to provide a convenient mechanism
to access mobile phone's peripheral
Q: What is WSP
Wireless Session Protocol (WSP) implements session
services of WAP. Sessions can be connection-oriented and connectionless and
they may be suspended and resumed at will.
Q: What is WTLS
Wireless Transport Layer Security protocal (WTLS)
does all cryptography oriented features of WAP. WTLS handles
encryption/decryption, user authentication and data
integrity. WTLS is based on the fixed network
Transport Layer Security protocal (TLS), formerly known as Secure Sockets Layer
Q: What is WTP
Wireless Transaction Protocol (WTP) is WAP's
transaction protocol that works between the session protocol WSP and security
protocol WTLS. WTP chops data packets into lower level datagrams and
concatenates received datagrams into useful data. WTP also keeps track of
received and sent packets and does re-transmissions and acknowledgment sending