THE WHATIS.COM WORD-OF-THE-DAY January 31, 2003 Java virtual machine
______________ TODAY'S SPONSOR: Free whitepapers for CIOs Download the key papers you need today to make better-informed decisions. Targeted categories include: Management and Strategy, Service Providers, Industry-Specific Applications, and E-business Technology. Click here to access the free SearchCIO.com white papers section. http://searchcio.techtarget.com/whitepapers3/0,,sid19,00.html ______________ TODAY'S WORD: Java virtual machine See our complete definition with hyperlinks at http://searchsolaris.techtarget.com/sDefinition/0,,sid12_gci876253,00.html A Java virtual machine (JVM), an implementation of the Java Virtual Machine Specification, interprets compiled Java binary code (called bytecode) for a computer's processor (or "hardware platform") so that it can perform a Java program's instructions. Java was designed to allow application programs to be built that could be run on any platform without having to be rewritten or recompiled by the programmer for each separate platform. A Java virtual machine makes this possible because it is aware of the specific instruction lengths and other particularities of the platform. The Java Virtual Machine Specification defines an abstract -- rather than a real -- machine or processor. The Specification specifies an instruction set, a set of registers, a stack, a "garbage heap," and a method area. Once a Java virtual machine has been implemented for a given platform, any Java program (which, after compilation, is called bytecode) can run on that platform. A Java virtual machine can either interpret the bytecode one instruction at a time (mapping it to a real processor instruction) or the bytecode can be compiled further for the real processor using what is called a just-in-time compiler. RELATED TERMS: Java http://searchsolaris.techtarget.com/sDefinition/0,,sid12_gci212415,00.html bytecode http://whatis.techtarget.com/definition/0,,sid9_gci211722,00.html instruction http://whatis.techtarget.com/definition/0,,sid9_gci212356,00.html platform http://searchcio.techtarget.com/sDefinition/0,,sid19_gci212797,00.html just-in-time compiler http://whatis.techtarget.com/definition/0,,sid9_gci212423,00.html SELECTED LINKS: David Reilly explains how a JVM works in "Inside Java: The Java Virtual Machine." http://www.javacoffeebreak.com/articles/inside_java/insidejava-jan99.html Chapter 5 of "Inside the Java Virtual Machine" provides an overview of the JVM internal architecture. http://www.artima.com/insidejvm/ed2/jvm.html The Java Virtual Machine Model shows the pathway a Java program follows as it executes. http://cne.gmu.edu/itcore/virtualmachine/jvm.htm SearchSolaris.com provides links to more information about the Java virtual machine. http://searchsolaris.techtarget.com/search/1,293876,sid12,00.html?query=JVM&ctype=SITE ______________________ QUIZ #35 | Common Vulnerabilities Take our quiz to test your knowledge about common security vulnerabilities. Learn how to defend your organization against them with the resources we've collected. http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci875285,00.html ______________________ WHATIS.COM POLL | How do you stay on top? 57% of the readers who responded to our last poll said they hadn't been sent for any IT training in 2002. We'd like to know: How do you stay on top of what's new in your area of IT? http://www.whatis.com/poll ______________________ REAL LIFE CHALLENGE | Upgrade to Win2k server or wait for .NET? Ned is an IT manager in a Windows NT environment with a couple of hundred workstations and several servers. Ned's CEO wants him to determine whether it would be better for the company upgrade to a Windows 2000 server, or wait until the Windows .NET server (now called Microsoft Windows Server 2003) comes out. Can you advise? http://whatis.discussions.techtarget.com/WebX?[EMAIL PROTECTED]@.1dcfae0e/211!viewtype=threadDate&skip=&expand= ______________________________ RECENT ADDITIONS AND UPDATES [1] R/2 http://searchsap.techtarget.com/sDefinition/0,,sid21_gci876431,00.html [2] heuristics http://searchsecurity.techtarget.com/sDefinition/0,,sid14_gci876400,00.html [3] mail transfer agent http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci876011,00.html [4] X# http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci875257,00.html [5] Advanced Planner and Optimizer http://searchsap.techtarget.com/sDefinition/0,,sid21_gci874121,00.html ____________________________________________________________________ ::::::::::::::::::: WHATIS.COM CONTACTS ::::::::::::::::::: LOWELL THING, Site Editor ([EMAIL PROTECTED]) ____________________________________________________________________ MARGARET ROUSE, Associate Editor ([EMAIL PROTECTED]) ___________________________________________________________________ :::::::::::::::::::: ABOUT THIS NEWSLETTER ::::::::::::::::::::: Published by TechTarget (http://www.techtarget.com) TechTarget - The Most Targeted IT Media Copyright 2003, All Rights Reserved. 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