Chapter   1

Introduction

These release notes provide information about Sun’s reference implementation of the Connected, Limited Device Configuration Specification, version 1.0 for the Java™ 2 Platform, Micro Edition (J2ME™).

CLDC 1.0 is the result of a Java Community Process effort (JSR-30) that has standardized a small-footprint Java™ platform for resource-constrained consumer devices. The CLDC specification effort was done in collaboration with 18 companies representing different industries. Target devices for CLDC are characterized generally as follows:

at least 160 kilobytes of total memory, including both RAM and flash or ROM, available for the Java platform.
Limited power, often battery powered operation.
Connectivity to some kind of a network, often with a wireless, intermittent connection and with limited (often 9600 bps or less) bandwidth.
User interfaces with varying degrees of sophistication down to and including none.

Cell phones, two-way pagers, personal digital assistants (PDAs), pocket organizers, home appliances, and point of sale terminals are some, but not all, of the devices that might be supported by CLDC.

The CLDC reference implementation runs on Sun’s K Virtual Machine (KVM) implementation that is provided as part of this release.

The CLDC Specification document is available for public downloading at
http://jcp.org/aboutJava/communityprocess/final/jsr030/index.html.

Note that CLDC is intended to serve as the “lowest common denominator” building block for various kinds of resource-constrained, Java Powered™ devices. As such, CLDC is not a complete, self-sufficient solution; it needs to be complemented by profiles. For instance, all user interface aspects are outside the scope of CLDC Specification. A parallel Java Community Process effort (JSR-37) called Mobile Information Device Profile (MIDP) has defined the necessary remaining Java platform features and libraries for two-way communication devices such as cell phones, while another effort (JSR-75) is focusing on PDA-type devices. Other profiles for other vertical markets or device categories might be defined later.

1.1 Supported Platforms

The J2ME CLDC Reference Implementation runs on Solaris and Win32 platforms.
A CLDC-compliant port for Linux is also provided as part of this package.

The CLDC implementation for the Palm OS is no longer available. If you are interested in downloading a Java platform for the Palm OS, please refer to the MIDP for Palm OS product website:
http://java.sun.com/products/midp/palmOS.html.

1.2 Items Included in This Release

This release includes the source code and binaries for:

K Virtual Machine (KVM)
Preverifier tool (for preverifying Java class files)
JavaCodeCompact tool (for prelinking/preloading system classes into KVM)
Debug agent (for plugging the KVM into a third party debugging environment)
Java Application Manager (JAM) reference implementation
CLDC 1.0 class libraries
Additional Java libraries (network protocol implementations located in package com.sun.cldc)

Please refer to the KVM Porting Guide (KVM 1.0.4), (Sun Microsystems, Inc., 2002) (provided in this package) for more information on the preverifier tool, JavaCodeCompact tool, debug agent and the JAM.

Note – The CLDC 1.0.4 release does not include the old com.sun.kjava (Spotlet) GUI APIs or the Palm port of the KVM that were available in the early releases of the KVM. A Palm implementation of the K Virtual Machine with the MIDP APIs is available separately from the MIDP product web site
http://java.sun.com/products/midp
See the link “MIDP for Palm OS available for download.”
http://java.sun.com/products/midp/palmOS.html

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Note – The network protocol implementation classes provided in package com.sun.cldc are not officially part of the CLDC reference implementation or CLDC Specification. These classes have been provided to facilitate porting and testing efforts, and might change or be removed in future releases of this software.

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The release includes the following documentation:

J2ME CLDC Reference Implementation Release Notes (this document)
CLDC API document (javadoc), version 1.0 (regenerated from the latest libraries)
KVM Porting Guide (KVM 1.0.4), (Sun Microsystems, Inc., 2002)
KVM Debug Wire Protocol (KDWP) Specification, (Sun Microsystems, Inc., 2001)
K Native Interface (KNI) Specification, (Sun Microsystems, Inc., 2001)

1.3 Differences Between CLDC 1.0.4 and CLDC 1.0.3 Releases

CLDC 1.0.4 is primarily a maintenance release that contains various bug fixes as well as some new functionality.

The main features of CLDC 1.0.4 compared to CLDC 1.0.3 include:

Support for the K Native Interface (KNI).
More portable runtime verifier implementation.
Preverifier and ROMizer enhancements to include JDK 1.4 Compatibility.
Various minor bug fixes and enhancements.

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Note – Apart from a number of bug fixes and comment updates, the CLDC libraries between CLDC 1.0.3 and CLDC 1.0.4 releases have not changed. The libraries provided with this release conform to the CLDC Specification version 1.0.

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For most up-to-date information, refer to the CLDC product website
( http://java.sun.com/products/cldc).

1.4 Prerequisites and Dependencies

For more details on the Connected, Limited Device Configuration standardization effort, please refer to the Connected, Limited Device Configuration Specification, version 1.0, Sun Microsystems, Inc.:
http://jcp.org/aboutJava/communityprocess/final/jsr030/index.html

Please refer to the KVM Porting Guide (KVM 1.0.4), (Sun Microsystems, Inc., 2002) for information about porting the K Virtual Machine to new platforms.

1.5 Frequently Asked Questions

A Frequently Asked Questions (FAQ) document for the CLDC reference implementation is available at the following website:

http://java.sun.com/products/cldc/faqs.html

The following FAQ documents might also be useful:

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

     http://java.sun.com/products/j2mewtoolkit/FAQ.html

 

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Release Notes CLDC, 1.0.4

 

Copyright © 2002 Sun Microsystems, Inc. All rights reserved.