Connected Limited Device Configuration

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (July 2007)

The Connected Limited Device Configuration (CLDC) is a specification of a framework for Java ME applications targeted at devices with very limited resources such as pagers and mobile phones. The CLDC was developed under the Java Community Process as JSR 30 (CLDC 1.0) and JSR 139 (CLDC 1.1).

Typical requirements

16-bit CPU, a total of 160 KiB memory available to the Java platform, as well as a limited connection to some kind of network

Noteworthy limitations vis-a-vis J2SE runtime

Several APIs are absent entirely, and some APIs are altered such that code requires explicit changes to support CLDC. In particular, certain changes aren't just the absence of classes or interfaces, but actually change the inheritance hierarchy of the base class library. An example of this is the absence of Serializable which does not appear in the base class library. All java.lang.* classes which normally are Serializable do not, therefore, implement this tagging interface. Other examples of what is not supported include the following, with those items not supported in later versions also not supported in earlier versions:

As of CLDC 1.1:

• Serializable interface not supported
• java.lang.Thread.interrupted() not supported.
• Parts of the reflection capabilities of the Java standard edition:
  • java.lang.reflect package and any of its classes not supported.
  • Methods on java.lang.Class which obtain Constructors or Methods or Fields.

As of CLDC 1.0:

• Floating point math and data structures not supported
• weak references not supported
• java.lang.Thread.interrupt() not supported

Platform minimum requirements

CLDC 1.0

• Minimum base memory: 160 KiB

CLDC 1.1

• Minimum base memory: 192 KiB.

Profiles

Mobile Information Device Profile

Designed for cell phones, it supports an LCD orientated GUI API, with MIDP 2.0 including a basic 2D gaming API. Applications written to use this profile are called MIDlets. Almost all new cell phones come with a MIDP implementation, and it is now the de facto standard for downloadable cell phone games.^{[citation needed]}

Information Module Profile

The Information Module Profile (JSR 195) is designed for vending machines, network cards, routers, telephone boxes and other systems with either simple or no display and some form of limited two way network access. Only APIs for application creation, storage, and network access are defined. These are a subset of the javax.microedition.io, rms and midlet packages in MIDP. Siemens Mobile and Nokia put forward this specification to the JCP.

DoJa Profile

The DoJa profile was designed for DoCoMo's i-mode mobile phone by NTT DoCoMo.

General APIs

java.io

A streamlined version of the java.io package found in the standard edition for doing Input/Output operations.

java.lang

Contains classes thought applicable to most java programs. This package contains standard java types like Integers and Strings as well as basic exceptions, math functions, system functions, threading and security functions.

java.util

A streamlined version of the java.util collection library. This package contains the collection classes like Vector and Hashtable. It also contains calendar and date classes.

See also

• Connected Device Configuration – or CDC, another framework for building Java ME applications
• Open Cable Application Platform for television cable boxes.

External links

• CLDC homepage
• JSR 139 (CLDC 1.1)
• JSR 30 (CLDC 1.0)
• JSR 242 "On-Ramp to cable" for television cable boxes.
• OSGi-based CLDC-framework