Java™ Language Specification, 2nd Edition

PTR Bullets

The definitive Java 2 reference for every developer: a long-awaited, complete update by the language's creators!

• Covers every key aspect of the core Java language.
• Classes, interface types, arrays, exceptions, expressions, threading, locks, and more.
• Detailed chapters on program execution, structure, and binary compatibility.

PTR Overview

For nearly five years, one book has served as the definitive reference to Java for all serious developers: The Java Language Specification, by James Gosling, Bill Joy, and Guy Steele. Now, these world-renowned Java authorities (along with new co-author Gilad Bracha) have delivered a monumental update. This completely revised Second Edition covers Java 2 SDK Standard Edition Version 1.3 with unprecedented depth and precision, offering the invaluable insights of Java's creators to every developer. The book begins by describing the lexical structure of the Java programming language, and how it builds on C and C++. Next, it introduces Java's types, values, and variables; then describes conversions and numeric promotions in Java. The authors introduce names, declarations, members, qualified names and naming conventions; the structure of Java programs and their organization into packages containing classes, interfaces, and subpackages. Classes are covered in depth, followed by interface types, arrays, exceptions, program initialization and execution, and a detailed review of binary compatibility. There are chapters on blocks and statements, expressions, definite assignment, threads and locks, and finally, a syntactic grammar for the Java language.MARKET:For all

Product Author Bios

Bill Joy is a cofounder of Sun Microsystems, where he led the company's technical strategy until September 2003, working on both hardware and software architecture. He is well known as the creator of the Berkeley version of the UNIX® operating system, for which he received a lifetime achievement award from the USENIX Association in 1993. He received the ACM Grace Murray Hopper Award in 1986. Joy has had a central role in shaping the Java programming language. He joined KPCB as Partner in January 2005.

Guy L. Steele Jr. is a Sun Fellow at Sun Microsystems Laboratories, where he is responsible for research in language design and implementation strategies, parallel algorithms, and computer arithmetic. He is well known as the cocreator of the Scheme programming language and for his reference books for the C programming language (with Samuel Harbison) and for the Common Lisp programming language. Steele received the ACM Grace Murray Hopper Award in 1988 and was named an ACM Fellow in 1994, a member of the National Academy of Engineering in 2001, and a fellow of the American Academy of Arts and Science in 2002. He also received the 1996 ACM SIGPLAN Programming Languages Achievement Award and the 2005 Dr. Dobb's Journal Excellence in Programming Award.

Gilad Bracha is Computational Theologist at Sun Microsystems, and a researcher in the area of object-oriented programming. Prior to joining Sun, he worked on Strongtalk,™ the Animorphic Smalltalk System. He holds a B.S. in mathematics and computer science from Ben Gurion University in Israel and a Ph.D. in computer science from the University of Utah.

James Gosling is a Fellow and Chief Technology Officer of Sun's Developer Products group, the creator of the Java programming language, and one of the computer industry's most noted programmers. He is the 1996 recipient of Software Development's "Programming Excellence Award." He previously developed NeWS, Sun's network-extensible window system, and was a principal in the Andrew project at Carnegie Mellon University, where he earned a Ph.D. in computer science.

Written by the inventors of the technology, The Java™ Language Specification, Second Edition is the definitive technical reference for the Java™ programming language. If you want to know the precise meaning of the language's constructs, this is the source for you.

The book provides complete, accurate, and detailed coverage of the syntax and semantics of the Java programming language. It describes all aspects of the language, including the semantics of all types, statements, and expressions, as well as threads and binary compatibility.

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Online Sample Chapter

Java's Lexical Structure

Table of Contents

Preface.


Preface to the Second Edition.


1. Introduction.

2. Grammars.

3. Lexical Structure.

4. Types, Values, and Variables.

5. Conversions and Promotions.

6. Names.

7. Packages.

8. Classes.

9. Interfaces.

10. Arrays.

11. Exceptions.

12. Execution.

13. Binary Compatibility.

14. Blocks and Statements.

15. Expressions.

16. Definite Assignment.

17. Threads and Locks.

18. Syntax.

Index.


Credits.


Colophon. 0201310082T04062001

Preface

The Java™ programming language was originally called Oak, and was designed for use in embedded consumer-electronic applications by James Gosling. After several years of experience with the language, and significant contributions by Ed Frank, Patrick Naughton, Jonathan Payne, and Chris Warth it was retargeted to the Internet, renamed, and substantially revised to be the language specified here. The final form of the language was defined by James Gosling, Bill Joy, Guy Steele, Richard Tuck, Frank Yellin, and Arthur van Hoff, with help from Graham Hamil ton, Tim Lindholm, and many other friends and colleagues.

The Java programming language is a general-purpose concurrent class-based object-oriented programming language, specifically designed to have as few implementation dependencies as possible. It allows application developers to write a program once and then be able to run it everywhere on the Internet. This book attempts a complete specification of the syntax and semantics of the language. We intend that the behavior of every language construct is specified here, so that all implementations will accept the same programs. Except for timing dependencies or other non-determinisms and given sufficient time and sufficient memory space, a program written in the Java programming language should com pute the same result on all machines and in all implementations.

We believe that the Java programming language is a mature language, ready for widespread use. Nevertheless, we expect some evolution of the language in the years to come. We intend to manage this evolution in a way that is completely compatible with existing applications. To do this, we intend to make relatively few new versions of the language, and to distinguish each new version with a different filename extension. Compilers and systems will be able to support the several ver sions simultannously, with complete compatibility.

Much research and experimentation with the Java platform is already under way. We encourage this work, and will continue to cooperate with external groups to explore improvements to the language and platform. For example, we have already received several interesting proposals for parameterized types. In techni cally difficult areas, near the state of the art, this kind of research collaboration is essential.

We acknowledge and thank the many people who have contributed to this book through their excellent feedback, assistance and encouragement: Particularly thorough, careful, and thoughtful reviews of drafts were provided by Tom Cargill, Peter Deutsch, Paul Hilfinger, Masayuki Ida, David Moon, Steven Muchnick, Charles L. Perkins, Chris Van Wyk, Steve Vinoski, Philip Wadler, Daniel Weinreb, and Kenneth Zadeck. We are very grateful for their extraordinary volunteer efforts.

We are also grateful for reviews, questions, comments, and suggestions from Stephen Adams, Bowen Alpern, Glenn Ammons, Leonid Arbuzov, Kim Bruce, Edwin Chan, David Chase, Pavel Curtis, Drew Dean, William Dietz, David Dill, Patrick Dussud, Ed Felten, John Giannandrea, John Gilmore, Charles Gust, Warren Harris, Lee Hasiuk, Mike Hendrickson, Mark Hill, Urs Hoelzle, Roger Hoover, Susan Flynn Hummel, Christopher Jang, Mick Jordan, Mukesh Kacker, Peter Kessler, James Larus, Derek Lieber, Bill McKeeman, Steve Naroff, Evi Nemeth, Robert O'Callahan, Dave Papay, Craig Partridge, Scott Pfeffer, Eric Raymond, Jim Roskind, Jim Russell, William Scherlis, Edith Schonberg, Anthony Scian, Matthew Self, Janice Shepherd, Kathy Stark, Barbara Steele, Rob Strom, William Waite, Greg Weeks, and Bob Wilson. (This list was generated semi-automatically from our E-mail records. We apologize if we have omitted anyone.)

The feedback from all these reviewers was invaluable to us in improving the definition of the language as well as the form of the presentation in this book. We thank them for their diligence. Any remaining errors in this book---we hope they are few---are our responsibility and not theirs.

We thank Francesca Freedman and Doug Kramer for assistance with matters of typography and layout. We thank Dan Mills of Adobe Systems Incorporated for assistance in exploring possible choices of typefaces.

Many of our colleagues at Sun Microsystems have helped us in one way or another. Lisa Friendly, our series editor, managed our relationship with Addison Wesley. Susan Stambaugh managed the distribution of many hundreds of copies of drafts to reviewers. We received valuable assistance and technical advice from Ben Adida, Ole Agesen, Ken Arnold, Rick Cattell, Asmus Freytag, Norm Hardy, Steve Heller, David Hough, Doug Kramer, Nancy Lee, Marianne Mueller, Akira Tanaka, Greg Tarsy, David Ungar, Jim Waldo, Ann Wollrath, Geoff Wyant, and Derek White. We thank Alan Baratz, David Bowen, Mike Clary, John Doerr, Jon Kannegaard, Eric Schmidt, Bob Sproull, Bert Sutherland, and Scott McNealy for leadership and encouragement.

The on-line Bartleby Library of Columbia University, at URL: http://www.cc.columbia.edu/acis/bartleby/ was invaluable to us during the process of researching and verifying many of the quotations that are scattered throughout this book. Here is one example:

They lard their lean books with the fat of others' works.
---Robert Burton (1576--1640)

We are grateful to those who have toiled on Project Bartleby, for saving us a great deal of effort and reawakening our appreciation for the works of Walt Whitman.

We are thankful for the tools and services we had at our disposal in writing this book: telephones, overnight delivery, desktop workstations, laser printers, photocopiers, text formatting and page layout software, fonts, electronic mail, the World Wide Web, and, of course, the Internet. We live in three different states, scattered across a continent, but collaboration with each other and with our reviewers has seemed almost effortless. Kudos to the thousands of people who have worked over the years to make these excellent tools and services work quickly and reliably.

Mike Hendrickson, Katie Duffy, Simone Payment, and Rosa Aim"e GonzSumlez of Addison-Wesley were very helpful, encouraging, and patient during the long process of bringing this book to print. We also thank the copy editors. Rosemary Simpson worked hard, on a very tight schedule, to create the index. We got into the act at the last minute, however; blame us and not her for any jokes you may find hidden therein. Finally, we are grateful to our families and friends for their love and support during this last, crazy, year. In their book The C Programming Language, Brian Kernighan and Dennis Ritchie said that they felt that the C language "wears well as one's experience with it grows." If you like C, we think you will like the Java programming language.

We hope that it, too, wears well for you.

James Gosling--Cupertino, California
Bill Joy--Aspen, Colorado
Guy Steele--Chelmsford, Massachusetts
July, 1996

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