73 lines
6.8 KiB
HTML
73 lines
6.8 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Java JAR and class files" />
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<meta name="abstract" content="A Java ARchive (JAR) file is a file format that combines many files into one. The Java environment differs from other programming environments in that the Java compiler does not generate machine code for a hardware-specific instruction set. Instead, the Java compiler converts Java source code into Java virtual machine instructions, which Java class files store. You can use JAR files to store class files. The class file does not target a specific hardware platform, but instead targets the Java virtual machine architecture." />
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<meta name="description" content="A Java ARchive (JAR) file is a file format that combines many files into one. The Java environment differs from other programming environments in that the Java compiler does not generate machine code for a hardware-specific instruction set. Instead, the Java compiler converts Java source code into Java virtual machine instructions, which Java class files store. You can use JAR files to store class files. The class file does not target a specific hardware platform, but instead targets the Java virtual machine architecture." />
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<meta name="DC.Relation" scheme="URI" content="platform.htm" />
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<meta name="DC.Relation" scheme="URI" content="appsappl.htm" />
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<meta name="DC.Relation" scheme="URI" content="javavirm.htm" />
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<meta name="DC.Relation" scheme="URI" content="threads.htm" />
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<meta name="DC.Relation" scheme="URI" content="sunjdk.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="jarfile" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Java JAR and class files</title>
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</head>
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<body id="jarfile"><a name="jarfile"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Java JAR and class files</h1>
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<div><p>A Java™ ARchive (JAR) file is a file format that combines
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many files into one. The Java environment differs from other programming
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environments in that the Java compiler does not generate machine
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code for a hardware-specific instruction set. Instead, the Java compiler
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converts Java source code into Java virtual machine instructions, which Java class
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files store. You can use JAR files to store class files. The class file does
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not target a specific hardware platform, but instead targets the Java virtual
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machine architecture.</p>
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<p>You can use JAR as a general archiving tool and also to distribute Java programs
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of all types, including applets. Java applets download into a browser in
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a single Hypertext Transfer Protocol (HTTP) transaction rather than by opening
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a new connection for each piece. This method of downloading improves the speed
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at which an applet loads on a Web page and begins functioning.</p>
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<p>JAR is the only archive format that is cross-platform. JAR is also the
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only format that handles audio files and image files, as well as class files.
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JAR is an open standard, fully extendable format that is written in Java.</p>
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<p>The JAR format also supports compression, which reduces the size of the
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file and decreases download time. Additionally, an applet author may digitally
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sign individual entries in a JAR file to authenticate their origin.</p>
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<p>To update classes in JAR files, see the <a href="javaapi/tooldocs/windows/jar.html" target="_blank">Java jar tool</a>.</p>
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<p><strong>Java class
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files</strong> are stream files that are produced when a source file is compiled
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by the Java compiler. The class file contains tables that describe
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each field and method of the class. The file also contains the bytecodes for
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each method, static data, and descriptions that are used to represent Java objects.</p>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="platform.htm" title="The Java platform is the environment for developing and managing Java applets and applications. It consists of three primary components: the Java language, the Java packages, and the Java virtual machine.">Java platform</a></div>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="appsappl.htm" title="An applet is a Java program designed to be included in an HTML Web document. You can write your Java applet and include it in an HTML page, much in the same way an image is included. When you use a Java-enabled browser to view an HTML page that contains an applet, the applet's code is transferred to your system and is run by the browser's Java virtual machine.">Java applets and applications</a></div>
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<div><a href="javavirm.htm" title="The Java virtual machine is a runtime environment that you can add into a web browser or any operating system, such as IBM i5/OS. The Java virtual machine runs instructions that a Java compiler generates. It consists of a bytecode interpreter and runtime that allow Java class files to run on any platform, regardless of the platform on which they were originally developed.">Java virtual machine</a></div>
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<div><a href="threads.htm" title="A thread is a single independent stream that runs within a program. Java is a multithreaded programming language, so more than one thread may be running within the Java virtual machine at one time. Java threads provide a way for a Java program to perform multiple tasks at the same time. A thread is essentially a flow of control in a program.">Java threads</a></div>
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<div><a href="sunjdk.htm" title="The Java Development Kit (JDK) is software that is distributed by Sun Microsystems, Inc. for Java developers. It includes the Java interpreter, Java classes, and Java development tools: compiler, debugger, disassembler, appletviewer, stub file generator, and documentation generator.">Sun Microsystems, Inc. Java Development Kit</a></div>
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</div>
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</div>
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</body>
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</html>
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