需求分析：
Java开发中，Java 虚拟机绝对是一个重要的领域，它的意义是不可估量的。因为没有Java虚拟机（JVM）,Java程序如何启动，正常的运行呀。所以，研究和学习，或者，只是稍微的深入了解一点关于JVM的知识，绝对是可以对你的开发和学习产生莫大的积极意义。Java以开源而出名，你既可以直接作为一个应用者去开发你想要的程序，你也可以随时进入它的里面，探个究竟，这个是许多语言所无法比拟的。就像Delphi开发语言一样，可以深入可以简洁进行表面研究。很灵活。恩。也许这个就是自己喜欢它的原因吧，非常的强大，又非常的自由。看来，自己得稍微深入学习一下子呀。那么，就开始自己的Java虚拟机的分析之旅吧。恩。好JVM之旅，必定会满载而归呀。相信自己吧。
分析思路：
1.以Oracle官网发行的《Java Virtual Machine Specification》 入手，进入标准研究。
2.克服每一个抽象概念可能造成的学习上的绝大困难。
行文思路：
The Java TM virtual machine specification has been written to fully document the design of the Java virtual machine.It is essential for compiler writers who wish to target the Java virtual machine and for programmers who want to implement a compatible Java virtual machine.
总结一下：之所以写 《Java虚拟机说明书》 这本书，主要是为了想给那些致力于Java编译器的编写人员以及渴望实现兼容JVM的私人虚拟机的程序员提供全面的Jvm的规范性文档知识。
The Java virtual machine is an abstract machine.References to the Java virtual machine throughout this specification refer to this abstract machine rather than to Oracle's or any other specific implementation.This book serves as documentation for a concrete implementation of the Java virtual machine only as a blueprint documents a house.An implementation of the Java virtual machine (known as a runtime interpreter) must embody this specification,but is constrained by it only where absolutely necessary.
总结： 有点抽象了。
The Java virtual machine specified here is compatible with the Java Platform TM,Standard Edition 7,and supports the Java programming language specified in The Java TM Language Specification,Java SE 7 Edition(Addison-Wesley,2005).
We intend that this specification should sufficiently document the Java virtual machine to make possible compatible clean-room implementations.If you are considering constructing your own Java virtual machine implementation,feel free to contact us to obtain assistance to ensure the 100% compatibility of your implementation.
总结：最后一句话，很让自己感动。恩是啊。挺好的策略。
The virtual machine that evolved into the Java virtual machine was originally designed by James Gosling in 1992 to support the Oak programing language.The evolution into its present form occurred through the direct and indirect efforts of many people and spanned Sun's Green project,FirstPerson,Inc.,the LiveOak project,the Java Products Group,JavaSoft,and today,Oracle's Java Platform Group.The authors are grateful to the many contributors and supporters.
总结：；态度真的很不错。发展真的很不错。有点像是linux的特点。是有好些人一起努力，其中有的是自发贡献的呀。好呀。
This book began as internal project documentation.Kathy Walrath edited that early draft,helping to give the world its first look at the internals of the Java programming language.It was then converted to HTML by Mary Campione and was made available on our Web site before being expanded into book form.
The creation of The Java TM Virtual Machine Specification owes much to the support of the Java Products Group led by General Manager Ruth Hennigar,to the efforts of series editor Lisa Friendly,and to editor Mike Hendrickson and his group at Addison-Wesley.The many criticisms and suggestions received from reviewers of early online drafts,as well as drafts of the printed book ,improved its quality immensely.We owe special thanks to Richard Tuck for his careful review of the manuscript.
Particular thanks to Bill Joy whose comments,reviews,and guidance have contributed greatly to the completeness and accuracy of this book.
Notes on the Second Editon
The second edition of The Java TM Virtual Machine Specification brings the specification of the Java virtual machine up to date with the Java 2 platform,v1.2.It also includes many corrections and clarifications that update the presentation of the specification without changing the logical specification itself.We have attempted to correct typos and errata (hopefully without introducing new ones) and to add more detail to the specification where it was vague or ambiguous.In particular,we corrected a number of inconsistencies between the first edition of The Java TM Virtual Machine Specification and The Java TM Language Specification.
We thank the many readers who combed through the first edition of this book and brought problems to our attention.Several individuals and groups deserve special thanks for pointing out problems or contributing directly to the new material:
Carla Schroer and her teams of compatibility testers in Cupertino,California,and Novosibirsk,Russia(with special thanks to Leonid Arbouzov and Alexei Kaigorodov),painstakingly wrote compatiblility tests for each testable assertion in the first edition.In the process they uncovered many places where the originall specification was unclear or incomplete.
Jeroen Vermeulen,Janice Shepherd,Peter Bertelsen,Roly Perera,Joe Darcy,and Sandra Loosemore have all contributed comments and feedback that have improved this edition.
Marilyn Rash and Hilary Selby Polk of Addison Wesley Longman helped us to improve the readability and layout of this edition at the same time as we were incorporating all the technical changes.
Special thanks go to Gilad Bracha,who has brought a new level of rigor to the presentation and has been a major contributor to much of the new material,especially chapters 4 and 5 .His dedication to "computational theology" and his commitment to resolving inconsistencies between The Java TM Virtual Machine Specification and The Java TM Language Specification have benefited this book tremendously.
Notes on the Java SE 7 Editon
The Java SE 7 Edition of The Java TM Virtual Machine Specification incorporates all the changes that have been made to the specification since the Second Editon in 1999.In addition,numerous corrections and clarifications that have been made over time to align with popular implementations of the Java virtual machine,and with concepts common to the Java virtual machine and the Java programming language.
The Java SE 5.0 platform in 2004 brought momentous changes to the Java programming language but had a relatively muted effect on the design of the Java virtual machine.Additions were made to the class file format to support new Java language features such as generics and variable arity methods.
The Java SE 6 platform in 2006 saw no changes to the Java programming language but an entirely new approach to bytecode verification.It was Eva Rose who,in her masters thesis,first proposed a radical revision of JVM bytecode verification,in the context of the Java Card TM platform.This led first to an implementation for Java ME CLDC,and eventually to the revision of the Java SE verification process documented in chapter 4.
Sheng Liang implemented the Java ME CLDC verifier.Gilad Bracha was responsible for specifying the verifier,and Antero Taivalsaari led the overall specification of Java ME CLDC.Alessandro Coglio's analysis of Java bytecode verification was the most extensive,realistic,and thorough study of the topic,and contributed greatly to this specification.Wei Tao,together with Frank Yellin,Tim Lindholm and Gilad Bracha,implemented the Prolog verifier that formed the basis for the specification in both Java ME and Java SE.Wei then implemented the specification "for real" in the JVM.Later,Mingyao Yang improved the design and specification,and implemented the final version that shipped in the reference implementation of Java SE 6.
The specification benefited from the efforts of the JSR 202 expert group:xx,xxx,xxxx,……
The Java SE 7 platform in 2011 made good on the promise given in the First Edition of the Java Virtual Machine Specification in 1997:"In the future ,we will consider bounded extensions to the Java virtual machine to provide better support for other languages." It was Gilad Bracha who,in his work on hostwapping,anticipated the burden of the Java virtual machine's static type system on implementers of dynamically-typed languages.Consequently,the invokedynamic instruction and its supporting infrastructure were developed by John Rose and the JSR 292 expert group:xxx,xxx,xxxx,and xxx,with special contributions from xx and xxxxx.
More people than we can mention here have ,over time,contributed to the design and implementation of the Java virtual machine.The excellent performance we see in the JVMs of today would never have been possible without the technological foundation laid by David Ungar and his colleagues at the Self project at Sun Labs.This technology took a convoluted path,from Self on through the Animorphic Smalltalk VM to eventually become Oracle's HotSpot virtual machine.Lars Bak and Urs Hoelzle are the two people who were present through all these stages,and are more responsible than anyone else for the high performance we take for granted in JVMs today.
At the same time ,JVMs have also become very small.The KVM,designed for mobile devices,was pioneered by Antero Taivalsaari.The new verification technique specified in this edition was pioneered in the KVM context.
This specification has been significantly improved thanks to contributions from xx,xxx,xxx,……，and xx,as well as management by Uday ,x,xx,xxx,and xxx.Jon and Roger helped to ensure this specification is applicable to Java ME as much as Java SE.Leonid,xx,xx,and xx have done outstanding work in the Java Compatibility Kit to ensure this specification is both testable and tested.
