Klings.NoWires() - MIDP 1.0 Overview

Mobile Information Device Profile

The MIDP version 1.0a is the result of the work by a Java Community Process expert group JSR-37 consisting of a number of industrial partners. See links for details.

The MIDP 1.0a specification defines the architecture and the associated APIs needed for application development for mobile information devices.

Position in the J2ME architecture

MIDP
CLDC	Libraries
	KVM
Host Operating System

What is it?

The MIDP is a set of APIs that reside on top of the CLDC, providing features such as user interface, networking support and persistent storage.

MIDP 1.0a requirements

The MIDP target Mobile Information Devices (MIDs). To be classified as a MID a device should have the following minimum characteristics:

Display:
- Pixels: 96x54
- Display depth: 1-bit
- Pixel shape (aspect ratio): approximately 1:1
Input
- One- or two-handed keyboard or touch screen
Memory:
- 128 KB of non-volatile memory for the MIDP components
- 8 KB of non-volatile memory for application-created persistent data
- 32 KB of volatile memory for the Java runtime
Networking:
- Two-way, wireless, possibly intermittent, with limited bandwidth

What does it provide?

The MIDP adds the following packages on top of the CLDC:

javax.microediton.lcdui	Provides classes for user interface.
javax.microedition.midlet	Defines MIDP applications and the interactions between the application and the environment in which the application runs.
javax.microedition.rms	Provides persistent storage (Record Management System).

Since these packages are added on top of the CLDC, the MIDP API will also include all CLDC packages. It is worth noting that the MIDP adds a few extra interfaces and classes to existing packages in the CLDC. One of these is the HttpConnection interface which gives a framework for HTTP connections. The TimerTask class in java.util is another. Developers should therefore use the MIDP API when programming for MIDs, thus having access to all classes and interfaces provided by both the CLDC and the MIDP.

What does it not provide

Application management in terms of fetching, installing, selecting, running and removing MIDlets is not specified by the MIDP 1.0a. These issues are handled by the Application Manager, which is implemented in a device specific way by the OEM. Hence, application management is handled in a device specific way.

Note that application management is specified in the new MIDP 2.0.

Security

The MIDP 1.0a relies on the security model of the CLDC and specifies no additional security features except the semantics implied by the MIDP application model. The CLDC security model takes care of sufficient low-level and application-level security. Neither the CLDC or the MIDP 1.0a addresses end-to-end security. This was first introduced in MIDP 2.0.

Applications

MIDP applications are called MIDlets. The MIDP defines an application model to allow the limited resources of the device to be shared by multiple MIDlets. The application model defines the following:

What a MIDlet is.
How it is packaged.
Runtime environment available to the MIDlet.
The MIDlets behaviour so that the device kan manage its resources.
Packaging of MIDlets forming a MIDlet-suite.

Further information about MIDlets can be found under MIDlets.

More information

Specifications, APIs and other MIDP-related information can be found at:

http://java.sun.com/products/midp/

This page was last updated 14. Jul. 2006

Comments and feedback are highly appreciated.

You can reach me at: klings (at) nowires (dot) org

Klings.NoWires.J2ME()