Packaging Java software

What the problem is zAn executable program often consists of a very large number of files zIt's a nuisance to manage lots of files zWe like to "package" files into a single file for transportation and distribution zWe will explore several different packaging techniques zDifferent techniques are suitable for different situations and kinds of programs

Zip files zZip files are yconvenient single archive files ycompressed to save space yunderstood on all platforms  Most Windows users have probably used WinZip to unpack downloaded files  Fewer people have used WinZip to create zip files

Creating a.zip file, I  To create a.zip file, use WinZip Classic

Creating a.zip file, II  The WinZip Classic interface is easy to figure out yCreate a new archive yAdd files to it

jar files  A jar (Java archive) file is like a zip file  jar files were designed for Java, but can be used for any kind of files  The jar program is modeled after the UNIX tar program and works very much like it  tar originally stood for tape archive  jar files are particularly important for Applets  An tag can request a jar archive

Applets zHere's how an Applet gets loaded:  First, the browser requests the.html page containing the Applet  The tag causes the browser to request the file MyApplet.class  The browser's Java VM looks at this file and makes requests for other.class files that may be needed yThe applet starts and requests image and sound files zAll this two-way communication takes time zApplets load faster if they make fewer requests

Too many files zA complete Java Applet may consist of  many.class files  many.gif and/or.jpg files  possibly some.avi or.mp3 files yother file types may be included zMy most complex "animation" applet uses:  One.html file  Four.class files  Fifty.jpg files

Creating a jar file  Example command: jar cvf arch.jar *.class  cvf is a list of options  c -- create a jar file  v -- verbose; tell what you do as you do it  f -- use this jar file (almost always needed!)  arch.jar is the name of the file that is created  You don't need the.jar extension, but it's a good idea  *.class says to include all class files xYou can list additional files at the end

Unpacking a jar file  Example command: jar xvf arch.jar  cvf is a list of options  x -- extract from a jar file  v -- verbose; tell what you do as you do it  f -- use this jar file (almost always needed!)  arch.jar is the name of the file that is unpacked  You will also get a "manifest" file that may contain information about the jar file xMost of the time you can ignore the manifest file

Examining a jar file  Example command: jar tvf arch.jar  cvf is a list of options  t -- tell what is in the jar file  v -- verbose; tell what you do as you do it  f -- use this jar file (almost always needed!)  arch.jar is the name of the file that is examined

Using a jar file in an Applet zAn applet must be used from an HTML page zThe Applet tag has three required parameters:  code = the name of the main class file  height =, width = the size of the applet zTo use a jar file, we need a fourth parameter:  archive = name of the jar file zExample: y

Other options  InstallAnywhere is also widely used  InstallAnywhere Now! is the basic version  Now! is free  InstallShield Pro is widely used z "Industrial strength" z $995

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