Hi Techies,

Let's start posting J2ME interview questions and answers in this thread.

Thanks

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Prasanna Vignesh
MCPD | Web Developer

What is J2ME WTK?

What is CDC?

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.

What is CDPD?


Developed by Nortel Networks, Cellular Digital Packet Data (CDPD) is an open standard for supporting wireless Internet access from cellular devices. CDPD also supports Multicast, which allows content providers to efficiently broadcast information to many devices at the same time.

What is CLDC?

The Connected, Limited Device Configuration (CLDC) is a specification for a J2ME configuration. The CLDC is for devices with less than 512 KB or RAM available for the Java system and an intermittent (limited) network connection. It specifies a stripped-down Java virtual machine1 called the KVM as well as several APIs for fundamental application services. Three packages are minimalist versions of the J2SE java.lang, java.io, and java.util packages. A fourth package, javax.microedition.io, implements the Generic Connection Framework, a generalized API for making network connections.

What is cHTML?

Compact HTML (cHTML) is a subset of HTML which is designed for small devices. The major features of HTML that are excluded from cHTML are: JPEG image, Table, Image map, Multiple character fonts and styles, Background color and image, Frame and Style sheet.

What is CVM?

The Compact Virtual Machine (CVM) is an optimized Java virtual machine1 (JVM) that is used by the CDC.

What is Deck?

A deck is a collection of one or more WML cards that can be downloaded, to a mobile phone, as a single entity.

What is optional package ?

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.

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What is configuration?

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.

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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).

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what is preverification ?

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 isoff-device and done using the preverify tool. The second process is verification which is done on-device.

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What is KVM ?

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 CLDCspecifies 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.

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What is LCDUI ?

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.

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What is MIDlet suite ?

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.

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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.

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What is SIM ?

subscriber identity module that identify the subscriber and store some data.

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What 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.

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What is HLR?

The Home Location Register (HLR) is a database for permanent storage of subscriber data and service profiles.

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