Deploying Java applications as JAR files

SE-2030Dr. Mark L. Hornick

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How to package an application so that you can run it outside of Eclipse.

Consider an Eclipse project

SE-2030Dr. Mark L. Hornick

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This application consists of files in two directories, in packages called demo.app and demo.data

When you run an application from within Eclipse,

it (internally) issues the following command:java –cp “D:\My Docs\se2030\JARDemo\bin”

demo.app/JARDemoApp

java is the command that runs the Java Virtual Machine Found at C:\Program Files\Java\jdk1.6.0_03\bin\java.exe

JARDemoApp is the name of the main class

demo.app is the package containing the main class

(demo.data is the name of the package containing the MyData class)

-cp <classpath> specifies the base directory where the .class file(s) for the packages are located

Not including the package subdirectories

SE-2030Dr. Mark L. Hornick

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If your class files are in multiple file folders, you

must include them all:java –cp “D:\My Docs\se2030\JARDemo\bin; D:\MyDocs\

Documents\MSOE\Courses\Example Programs\se2030\UIHelper\bin” demo.app/JARDemoApp

-cp <classpath> specifies ALL base directories where the .class file(s) for the packages are located

Note that each directory is separated by a semicolon

SE-2030Dr. Mark L. Hornick

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A Java Archive (JAR) file enables you to bundle multiple files into a single archive file

A JAR file is essentially a ZIP file with specific contents:

The files you want to zip into the file .class files Source files (.java) if you want to enable debugging Javadoc files if you want to provide context-sensitive

help for the classes in the JAR file A manifest file (MANIFEST.MF)

Which specifies what’s in the JAR file

SE-2030Dr. Mark L. Hornick

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The jar utility can be used to create JAR files

jar cfm <jarfile> <manifest> -C <bin> <classfiles>jar is the command that runs the jar utility

Same as C:\Program Files\Java\jdk1.6.0_03\bin\jar.exe

jarfile is the name of the JAR file you want to create

manifest is the name of a file containing manifest informationNote : The contents of the manifest must be encoded in ansi.

-C <bin> specifies the location of the classfiles

classfiles specifies the files you want to place in the JAR file Separated by spaces Must include the full package folder path

SE-2030Dr. Mark L. Hornick

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To bundle files in the same directory into a JAR file:

jar cfm JARDemoApp.jar manifest.txt –C ./bin demo/app/JARDemoApp.class –C ./bin demo/data/Data.class

This assumes: you are issuing the jar command from within the directory of

D:\My Docs\se2030\JARDemo manifest.txt is in the same directory Demo/app and demo/data are the names of the packages such that all class files

are located in D:\My Docs\se2030\JARDemo\bin\demo\app

or D:\My Docs\se2030\JARDemo\bin\demo\data the capitalization of the class filename is identical to the capitalization of the class itself

(be careful on Windows because the OS is case-insensitive but Java is NOT)

SE-2030Dr. Mark L. Hornick

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Manifest details

Manifest.txt is an text file containing the following text:

Manifest-Version: 1.0

Created-By: 1.6.0_03-b05 (Sun Microsystems Inc.)

Main-Class: demo.app.JARDemoApp

SE-2030Dr. Mark L. Hornick

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To deploy your application, you just have to copy the JAR file to someplace (e.g. C:\temp) on the target PC

To run the application bundled within a JAR file, issue the following command:

java –jar “C:\temp\JARDemoApp.jar”

Or create a shortcut containing the above command

SE-2030Dr. Mark L. Hornick

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If your JAR file references other JAR files (like Helper.jar)…

The Manifest.txt must contain a reference to the location of the other JAR file(s):

Manifest-Version: 1.0

Created-By: 1.6.0_03-b05 (Sun Microsystems Inc.)

Main-Class: demo.app.JARDemoApp

Class-Path: ./Helper.jar

Note that ./ specifies that Helper.jar in this case can be found in the same directory folder as JARDemoApp.jar (i.e. they are both in C:\temp).

SE-2030Dr. Mark L. Hornick

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Online tutorial

“Packaging Programs in JAR files” http://java.sun.com/docs/books/tutorial/

deployment/jar/index.html

SE-2030Dr. Mark L. Hornick

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