1、 Reference numberISO/IEC 20970:2002(E)ISO/IEC 2002Information technology Programming languages, their environments and system software interfaces JEFF file format Technologies de linformation Langages de programmation, leurs environnements et interfaces de logiciel systme Format de fichier JEFF Nati
2、onal Standard of CanadaCAN/CSA-ISO/IEC 20970:04(ISO/IEC 20970:2002)International Standard ISO/IEC 20970:2002 (first edition, 2002-07-01) has been adopted without modification(IDT) as CSA Standard CAN/CSA-ISO/IEC 20970:04, which has been approved as a National Standard of Canadaby the Standards Counc
3、il of Canada.ISBN 1-55397-284-8 January 2004The Canadian Standards Association (CSA), The Standards Council of Canada is theunder whose auspices this National Standard has been coordinating body of the National Standards system, produced, was chartered in 1919 and accredited by a federation of indep
4、endent, autonomousthe Standards Council of Canada to the National organizations working towards the furtherStandards system in 1973. It is a not-for-profit, development and improvement of voluntarynonstatutory, voluntary membership association standardization in the national interest.engaged in stan
5、dards development and certification The principal objects of the Council are to foster activities. and promote voluntary standardization as a means CSA standards reflect a national consensus of of advancing the national economy, benefiting theproducers and users including manufacturers, health, safe
6、ty, and welfare of the public, assisting consumers, retailers, unions and professional and protecting the consumer, facilitating domestic organizations, and governmental agencies. The and international trade, and furthering internationalstandards are used widely by industry and commerce cooperation
7、in the field of standards.and often adopted by municipal, provincial, and A National Standard of Canada is a standard whichfederal governments in their regulations, particularly in has been approved by the Standards Council ofthe fields of health, safety, building and construction, Canada and one wh
8、ich reflects a reasonableand the environment. agreement among the views of a number of capableIndividuals, companies, and associations across individuals whose collective interests provide to theCanada indicate their support for CSAs standards greatest practicable extent a balance ofdevelopment by v
9、olunteering their time and skills to representation of producers, users, consumers, andCSA Committee work and supporting the Associations others with relevant interests, as may be appropriateobjectives through sustaining memberships. The more to the subject in hand. It normally is a standardthan 700
10、0 committee volunteers and the 2000 which is capable of making a significant and timelysustaining memberships together form CSAs total contribution to the national interest.membership from which its Directors are chosen. Approval of a standard as a National Standard ofSustaining memberships represen
11、t a major source of Canada indicates that a standard conforms to theincome for CSAs standards development activities. criteria and procedures established by the StandardsThe Association offers certification and testing Council of Canada. Approval does not refer to theservices in support of and as an
12、 extension to its technical content of the standard; this remains thestandards development activities. To ensure the continuing responsibility of the accreditedintegrity of its certification process, the Association standards-development organization.regularly and continually audits and inspects pro
13、ducts Those who have a need to apply standards arethat bear the CSA Mark. encouraged to use National Standards of CanadaIn addition to its head office and laboratory complex whenever practicable. These standards are subject in Toronto, CSA has regional branch offices in major to periodic review; the
14、refore, users are cautioned centres across Canada and inspection and testing to obtain the latest edition from the organizationagencies in eight countries. Since 1919, the preparing the standard.Association has developed the necessary expertise to The responsibility for approving National Standards
15、meet its corporate mission: CSA is an independent of Canada rests with theservice organization whose mission is to provide an Standards Council of Canadaopen and effective forum for activities facilitating the 270 Albert Street, Suite 200exchange of goods and services through the use of Ottawa, Onta
16、rio, K1P 6N7standards, certification and related services to meet Canadanational and international needs.For further information on CSA services, write toCanadian Standards Association5060 Spectrum Way, Suite 100Mississauga, Ontario, L4W 5N6CanadaAlthough the intended primary application of this Sta
17、ndard is stated in its Scope, it is importantto note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Canadian Standards AssociationCAN/CSA-ISO/IEC 20970:04 environments and system software interfaces JEFF file formatInfor
18、mation technology Programming languages, theirJanuary 2004 Canadian Standards Association CSA/1CAN/CSA-ISO/IEC 20970:04Information technology Programming languages, theirenvironments and system softwareinterfaces JEFF file formatCSA PrefaceStandards development within the Information Technology sect
19、or is harmonized with internationalstandards development. Through the CSA Technical Committee on Information Technology (TCIT),Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joint Technical Committee 1 onInformation Technology (ISO/IEC JTC1) for the Standards Council of Canada (
20、SCC), the ISO memberbody for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of theInternational Telecommunication Union (ITU), Canada participates in the International Telegraph andTelephone Consultative Committee (ITU-T).This International Standard was reviewed
21、by the CSA TCIT under the jurisdiction of the StrategicSteering Committee on Information Technology and deemed acceptable for use in Canada. (Acommittee membership list is available on request from the CSA Project Manager.) From time to time,ISO/IEC may publish addenda, corrigenda, etc. The CSA TCIT
22、 will review these documents for approvaland publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update orcontact a CSA Sales representative. This Standard has been formally approved, without modification, bythe Technical Committee and has been approved as a Natio
23、nal Standard of Canada by the StandardsCouncil of Canada.January 2004 Canadian Standards Association 2004All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission ofthe publisher. ISO/IEC material is reprinted with permission. Where the wo
24、rds “this International Standard” appear in thetext, they should be interpreted as “this National Standard of Canada”. Inquiries regarding this National Standard of Canada should be addressed to Canadian Standards Association 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6 1-800-4
25、63-6727 416-747-4044www.csa.caReference numberISO/IEC 20970:2002(E)ISO/IEC 2002INTERNATIONAL STANDARD ISO/IEC20970First edition2002-07-01Information technology Programming languages, their environments and system software interfaces JEFF file format Technologies de linformation Langages de programma
26、tion, leurs environnements et interfaces de logiciel systme Format de fichier JEFF ISO/IEC 20970:2002(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are
27、embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorpora
28、ted. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a
29、problem relating to it is found, please inform the Central Secretariat at the address given below. ISO/IEC 2002 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and
30、 microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.ch Web www.iso.ch ii ISO/IEC 2002 All rights res
31、ervedISO/IEC 20970:2002(E) ISO/IEC 2002 All rights reserved iiiContents Page Forewordv 0 Introductionvi 0.1 What is JEFF. vi 0.1.1 Benefits vi 1 Scope and normative references 1 1.1 Scope .1 1.2 Normative references.1 1.3 Definitions.2 2 Data Types 3 2.1 Basic Types3 2.2 Language Types.3 2.3 Strings
32、 3 2.3.1 Definition .3 2.3.2 Comparison.3 2.3.3 Representation3 2.4 Specific Types 4 2.4.1 Access Flags.4 2.4.2 Type Descriptor.5 2.4.3 Offsets.7 3 File Structure 8 3.1 Definitions.8 3.1.1 Fully Qualified Names .8 3.1.2 Internal Classes and External Classes .8 3.1.3 Fields and Methods.8 3.1.4 Field
33、Position.9 3.2 Conventions10 3.2.1 Notations .10 3.2.2 Byte Order.10 3.2.3 Alignment and Padding .10 3.3 Definition of the File Structures 11 3.3.1 File Header11 3.3.2 Class Section 14 3.3.2.1 Class Header .14 3.3.2.2 Interface Table.16 3.3.2.3 Referenced Class Table 16 3.3.2.4 Internal Field Table
34、17 3.3.2.5 Internal Method Table17 3.3.2.6 Referenced Field Table19 3.3.2.7 Referenced Method Table .19 3.3.2.8 Bytecode Block Structure.20 3.3.2.9 Exception Table List.21 3.3.2.10 Constant Data Section.21 3.3.3 Attributes Section 23 3.3.3.1 Attribute Type.24 3.3.3.2 Class Attributes24 3.3.3.3 Attri
35、bute Table25 3.3.4 Symbolic Data Section 25 3.3.5 Constant Data Pool .27 3.3.5.1 Constant Data Pool Structure 27 3.3.5.2 Descriptor.27 3.3.5.3 Method Descriptor28 3.3.6 Digital Signature28 ISO/IEC 20970:2002(E) iv ISO/IEC 2002 All rights reserved4 Bytecodes. 29 4.1 Principles 29 4.2 Translations29 4
36、.2.1 The tableswitch Opcode30 4.2.2 The lookupswitch Opcode.30 4.2.3 The new Opcode.31 4.2.4 Opcodes With a Class Operand .31 4.2.5 The newarray Opcode.32 4.2.6 The multianewarray Opcode .32 4.2.7 Field Opcodes .32 4.2.8 Method Opcodes.33 4.2.9 The ldc Opcodes .34 4.2.10 The wide Opcodes .34 4.2.11
37、The wide iinc Opcode35 4.2.12 Jump Opcodes 35 4.2.13 Long Jump Opcodes .36 4.2.14 The sipush Opcode .36 4.2.15 The newconstarray Opcode 37 4.3 Unchanged Instructions37 4.3.1 One-Byte Instructions37 4.3.2 Two-bytes Instructions 39 4.4 Complete Opcode Mnemonics by Opcode.39 5 Restrictions 41 ISO/IEC 2
38、0970:2002(E) ISO/IEC 2002 All rights reserved vForeword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the develo
39、pment of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-government
40、al, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of the
41、 joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. At
42、tention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. ISO/IEC 20970 was prepared by J Consortium and was adopted, under the PAS procedu
43、re, by Joint Technical Committee ISO/IEC JTC 1, Information technology, in parallel with its approval by national bodies of ISO and IEC. J Consortium, Inc. (“J Consortium”) has granted permission to ISO and IEC to use the trademark JEFF for products that comply with ISO/IEC 20970. Thus, implementers
44、 of ISO/IEC 20970 may use the J Consortiums JEFF trademark in connection with products that fully meet the requirements of ISO/IEC 20970. ISO/IEC 20970:2002(E) vi ISO/IEC 2002 All rights reserved0 Introduction 0.1 What is JEFF This International Standard describes the JEFF File Format. This format i
45、s designed to download and store on a platform object oriented programs written in portable code. The distribution of applications is not the target of this specification. The goal of this International Standard is to provide a ready-for-execution format allowing programs to be executed directly fro
46、m static memory, thus avoiding the necessity to recopy classes into dynamic runtime memory for execution. The constraints put on the design of JEFF are the following: Any set of class files must be translatable into a single JEFF file. JEFF must be a ready-for-execution format. A virtual machine can
47、 use it efficiently, directly from static memory (ROM, flash memory). No copy in dynamic runtime memory or extra data modification shall be needed. All the standard behaviors and features of a virtual machine such as Java virtual machine must be reproducible using JEFF. In particular, JEFF must faci
48、litate “symbolic linking” of classes. The replacement of a class definition by another class definition having a compatible signature (same class name, same fields and same method signatures) must not require any modifications in the other class definitions. The main consequences of these choices ar
49、e: A JEFF file can contain several classes from several packages. The content can be a complete application, parts of it, or only one class. To allow “symbolic linking” of classes, the references between classes must be kept at the symbolic level, even within a single JEFF file. The binary content of a JEFF file is adapted to be efficiently read by a wide range of processors (with different byte orders, alignments, etc.). JEFF is also a highly efficient format for the dynamic downloading of class def
