PDF 100% Pure Java Cookbook

100% Pure JavaTM Cookbook

Guidelines for achieving the 100% Pure Java Standard

Revision 4.0

Sun Microsystems, Inc. 901 San Antonio Road Palo Alto, California 94303 USA

Copyrights

? 2000 Sun Microsystems, Inc. All rights reserved. 901 San Antonio Road, Palo Alto, California 94043, U.S.A.

This product and related documentation are protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation. No part of this product or related documentation may be reproduced in any form by any means without prior written authorization of Sun and its licensors, if any.

Restricted Rights Legend

Use, duplication, or disclosure by the United States Government is subject to the restrictions set forth in DFARS 252.227-7013 (c)(1)(ii) and FAR 52.227-19.

The product described in this manual may be protected by one or more U.S. patents, foreign patents, or pending applications.

Trademarks

Sun, the Sun logo, Sun Microsystems, Java, Java Compatible, 100% Pure Java, JavaStar, JavaPureCheck, JavaBeans, Java 2D, Solaris,Write Once, Run Anywhere, JDK, Java Development Kit Standard Edition, JDBC, JavaSpin, HotJava, The Network Is The Computer, and JavaStation are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and certain other countries. UNIX is a registered trademark in the United States and other countries, exclusively licensed through X/Open Company, Ltd. All other product names mentioned herein are the trademarks of their respective owners.

Netscape and Netscape Navigator are trademarks of Netscape Communications Corporation in the United States and other countries.

THIS PUBLICATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.

THIS PUBLICATION COULD INCLUDE TECHNICAL INACCURACIES OR TYPOGRAPHICAL ERRORS. CHANGES ARE PERIODICALLY ADDED TO THE INFORMATION HEREIN; THESE CHANGES WILL BE INCORPORATED IN NEW EDITIONS OF THE PUBLICATION. SUN MICROSYSTEMS, INC. MAY MAKE IMPROVEMENTS AND/OR CHANGES IN THE PRODUCT(S) AND/OR THE PROGRAM(S) DESCRIBED IN THIS PUBLICATION AT ANY TIME.

Revision History

4/97 - 1.0

First release

5/97 - 1.1

Minor updates

4/98 - 2.0

Added certification instructions for beans

Introduced new feature based dynamic testing requirements

Dropped code coverage requirements

Added instructions for recertification

4/99 - 2.1

Added certification instructions for servlets

Added guidelines for certification under 1.2 runtime environments

Updated recertification requirements

Added guidelines for certifying hybrid programs

Added FAQ

10/99 - 3.0

Reorganized and updated

3/00 - 3.1

Reorganized and updated

10/00 - 4.0

Formerly "100% Pure Java Certification Guide", rewritten to remove the certification

process and branding program.

Table of Contents

Introduction

The 100% Pure JavaTM Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1

About this Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 2 100% Pure Java Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 3 Online Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 3

What is the 100% Pure Java Standard? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4 API Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4 Common Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 4

Should I Comply With The Purity Standard?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 5 The "Suggested Compliance Evaluation Criteria?" Checklist . . . . . . . . . . . . . . . . . 1 - 5

Understanding Portability & Purity

Standards for Portability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1 The Purpose of the Purity Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1 Which JavaTM API? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2

Understanding `Purity'. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2 Purity is Not Goodness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3 Portability vs. Purity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3

Rules of Purity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 4 The Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 5

Revision Date: 10/00

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Guidelines for Developing Pure Programs

How to Develop a Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1 Use of Native Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3 Use of exec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4 Failure to Use the Portability Features of Java Core API . . . . . . . . . . . . . . . . . . . . . . 3 - 4 Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4 Direct Use of AWT Peer Classes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4 Misuse of System.exit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 5 Use of Hard-Coded File Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 5 JDBCTM Driver Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 7 Line Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 8 Unportable Command-Line Programs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 9 Command Line Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 9 Internationalization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 9 Unicode Rendering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 9 File I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 10 GUI Element Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 10 GUI Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 10 GUI Appearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 10 The Paint Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 11 Mixed Event Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 12 Use of Deprecated Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 12

The Object.hashCode and Object.equals Methods . . . . . . . . . 3 - 12

Installation Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 13 Hostname Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 13 Pluggable Look and Feel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 14 Mixing Classes Compiled on Different Versions of the Java Platform . . . . . . . . . 3 - 15

Portability Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 16 Security Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 16 Coping with Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 17

Explanations of Purity Problems and Variances

Explanations of Purity Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1 Report Information Categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1 Explanations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2 Warnings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2 Possible Hardcoded Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2 Mixing the 1.0 and 1.1 Event Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2 Dynamically Loaded Classes:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2 Object is Compiled for a Previous (Java Development Kit) release . . . . . . . . . . 4 - 3 Unsupported Pluggable Look and Feel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 3 Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4 Constant Strings with OS-Specific Syntax Used in I/O Class Constructors . . . 4 - 4 Peer Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

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100% Pure Java Cookbook

Use of Native Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

Use of java.lang.Runtime.exec. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

Injection into Core Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4 Undefined Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

Undocumented Internal sun.* Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4

Variances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5 Types of Variances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5 The Variances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5 Variances for Program Invocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 5 Variances for Programs Containing Native Code . . . . . . . . . . . . . . . . . . . . . . . . 4 - 7 Miscellaneous Variances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 9

Available Java Platforms

Platforms for Java Applications and Applets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A - 1 Available Platforms for Java Application Environment Version 1.0.2 . . . . . . . . . .A - 2 Available Platforms for Java Application Environment 1.1 . . . . . . . . . . . . . . . . . . .A - 3 Available Platforms for Java Application Environment 1.2 . . . . . . . . . . . . . . . . . . .A - 4

Frequently Asked Questions for Purity

Frequently Asked Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B - 1

Revision Date: 10/00

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