The Java Community Process(SM) Program - JSRs: Java Specification Requests - detail JSR# 139

Note: this JSR was completed under JCP 2.1.

Updates to Original JSR

The following information has been updated from the original proposal.

2008年09月19日:

Maintenance Lead: Roger Riggs, Sun Microsystems, Inc.

E-Mail Address: roger.riggs@sun.com

Telephone Number: +1 781 442 0539

Fax Number: +1 781 442 1610

2006年12月20日:

Maintenance Lead: Jonathan Courtney, Sun Microsystems, Inc.

E-Mail Address: jonathan.courtney@sun.com

Telephone Number: +1 214 693 3327

Fax Number: +1 972 235 5727

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The Original Java Specification Request (JSR)

Section 1. Identification

Submitting Member: Antero Taivalsaari, Sun Microsystems, Inc.

Name of Contact Person: Antero Taivalsaari, Sun Microsystems, Inc.

E-Mail Address: antero.taivalsaari@sun.com

Telephone Number: +1 408 343-1444

Fax Number: +1 408 517-5460

Specification Lead: Antero Taivalsaari, Sun Microsystems, Inc.

E-Mail Address: antero.taivalsaari@sun.com

Telephone Number: +1 408 343-1444

Fax Number: +1 408 517-5460

Initial Expert Group Membership:

Sun
Motorola
Nokia
NTT DoCoMo
RIM
Siemens

The Expert Group is likely to include the majority of the companies that participated in the CLDC 1.0 (JSR-30) specification process. Additional companies will also have the opportunity to participate.

If necessary, participation will be limited to about 20-25 companies to allow fruitful expert group work.

Section 2: Request

2.1 Please describe the proposed Specification:

This specification will define a revised version of the J2ME Connected, Limited Device Configuration (CLDC).

J2ME CLDC defines a standard platform for small, resource-constrained, connected devices characterized as follows:

• At least 160 kilobytes of total memory available for the Java platform.
• Processor speed starting from 8-32 MHz.
• 16/32 bit processor.
• Limited power, usually battery operation.
• Connectivity to some type of network, with possibly limited (9600 bps or less) bandwidth.
• High-volume manufacturing (usually millions of units).
• User interfaces with varying degrees of sophistication down to and including none.

The actual device characteristics and memory footprint requirements for the next-generation CLDC will be determined by the Expert Group. Cell phones, two-way pagers, personal digital assistants, and small appliances are some, but not all, of the devices that may be supported by this configuration specification.

The general goal of the proposed new specification is to make CLDC compliant with the Java Language and Virtual Machine Specifications by possibly reintroducing features such as floating point support and improved error handling capabilities (especially class loading errors and verification errors).

In contrast, the CLDC libraries will not be extended significantly in order to meet the strict memory footprint requirement demanded by CLDC target devices. The expert group will investigate the possibility of adding a minimal security manager and/or class unloading support. Additional libraries are more appropriately added to profiles defined on top of CLDC, so that CLDC can stay small, simple and broadly applicable.

Devices that require significantly more complete Java libraries should use the J2ME Connected Device Configuration (CDC) instead.

Additional goals for the proposed specification include:

• Backward compatibility with CLDC 1.0.
• Continued focus on small, resource-constrained, connected devices.
• Continued focus on generality (instead of focusing on any particular device category).
• Continued focus on maintaining the tight footprint objectives to limit the API growth.
• Utilize experiences learned from CLDC 1.0 deployments to fine tune the specification.

2.2 What is the target Java platform? (i.e., desktop, server, personal, embedded, card, etc.)

Java 2 Micro Edition (J2ME^TM).

2.3 What need of the Java community will be addressed by the proposed specification?

Provide an enhanced, extended version of the standard CLDC platform for small, connected devices. CLDC is already in widespread usage, and there is a need for enhancements and extensions.

2.4 Why isn't this need met by existing specifications?

J2ME CLDC does not currently include certain features that are required by device manufacturers and application developers.

J2ME CDC is too large to meet the strict memory footprint requirements that are characteristic of CLDC target devices.

2.5 Please give a short description of the underlying technology or technologies:

J2ME
CLDC 1.0
MIDP 1.0

2.6 Is there a proposed package name for the API Specification? (i.e., javapi.something, org.something, etc.)

The APIs defined by CLDC go into the following packages:

• For new packages: javax.microedition.*
• For packages derived from J2SE: java.*

2.7 Does the proposed specification have any dependencies on specific operating systems, CPUs, or I/O devices that you know of?

No. However, the proposed specification assumes that the target devices will meet the following broad technical requirements/characteristics:

• At least 160 kilobytes of total memory available for the Java platform.
• Processor speed starting from 8-32 MHz.
• 16/32 bit processor.
• Limited power, usually battery operation.
• Connectivity to some type of network, although with possibly limited (9600 bps or less) bandwidth.
• High-volume manufacturing (possibly millions of units).
• User interfaces with varying degrees of sophistication down to and including none.

The actual memory footprint requirements for the next-generation CLDC will be decided by the Expert Group. Because of added functionality, it can be anticipated that footprint requirements will be somewhat larger than those of CLDC 1.0.

2.8 Are there any security issues that cannot be addressed by the current security model?

Possibly. The Expert Group will investigate the feasibility of extending the current CLDC 1.0 security model.

2.9 Are there any internationalization or localization issues?

CLDC 1.0 covers internationalization but not localization.

2.10 Are there any existing specifications that might be rendered obsolete, deprecated, or in need of revision as a result of this work?

No.

2.11 Please describe the anticipated schedule for the development of this specification.

The final version of this specification should be available in early 2002.

2.12 Please describe the anticipated working model for the Expert Group working on developing this specification.

This group will operate along similar lines to the CLDC 1.0 Expert Group (JSR-30). Meetings will be held roughly every 8-10 weeks, and a formal mailing list will be set up. It is likely that the Expert Group will work in close collaboration with the next-generation MIDP expert group (JSR-118).

Section 3: Contributions

3.1 Please list any existing documents, specifications, or implementations that
describe the technology. Please include links to the documents if they are publicly available.

The Java^TM Language Specification, Second Edition,
James Gosling, Bill Joy, Guy L. Steele, and Gilad Bracha.
Addison-Wesley, 2000, ISBN 0-201-31008-2

The Java^TM Virtual Machine Specification, Second Edition,
Tim Lindholm and Frank Yellin.
Addison-Wesley, 1999, ISBN 0-201-43294-3

Programming Wireless Devices with the Java^TM 2 Platform, Micro Edition
Roger Riggs, Antero Taivalsaari, and Mark VandenBrink.
Addison-Wesley, 2001, ISBN 0-201-74627-1.

Connected, Limited Device Configuration Specification version 1.0,
http://java.sun.com/aboutJava/communityprocess/final/jsr030/

Mobile Information Device Profile Specification, version 1.0a