How to run java class from .jar archive?

Question

Need to run particular java class from jar package through unix console. Is it possible? Thanks

kindly check this http://stackoverflow.com/questions/6780678/run-class-in-jar-file — Milesh, Oct 09 '12 at 13:34

score 4 · Accepted Answer · answered Oct 09 '12 at 13:36

4

It's not possible to call a specific method of a class from a terminal.

You can only call the main method with java -cp JarFile.jar package.ClassName

Or, if your jar contains a manifest file, then you can do: java -jar pJarFile.jar.

answered Oct 09 '12 at 13:36

Mesop

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@psed In that case, you have to do `java -cp JarFile.jar package.ClassName` with `package.ClassName` being the class containing the main method. – Mesop Oct 09 '12 at 13:37
Yes, there is a class with "main" method. – johnny-b-goode Oct 09 '12 at 13:39
Finally. Works. Thanks a lot! – johnny-b-goode Oct 09 '12 at 13:40
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@psed I'm glad I was able to help. – Mesop Oct 09 '12 at 13:41
I am getting could not find or load main class. I am running this in solaris – Julie Nov 17 '16 at 17:52

Mudassir Hasan · Answer 2 · 2012-10-09T13:38:29.347

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Use

java -cp myJar.jar myClass

The -cp option is used when setting up the classpath manually ie give full path of location of jar file and then run command

Eg.

C:> java -cp C:\java\MyClasses\myJar.jar myClass

edited Oct 09 '12 at 13:38

answered Oct 09 '12 at 13:33

Mudassir Hasan

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Got "NoClassDefFoundException" – johnny-b-goode Oct 09 '12 at 13:35
Are quotes for -cp argument needed? – johnny-b-goode Oct 09 '12 at 13:39

score 2 · Answer 3 · answered Oct 09 '12 at 13:47

For running a jar file you can have either of following approach. Both of them require that you know the fully qualified name of the class where main(String[] arg) method is written.

Say your class containing main method is com.myclass.MainClass

You can run the jar directly. Keep the jar file at the location from where you are running this command

java -cp yourjarfile.jar com.myclass.MainClass
Create a manifest manifest.mf file with following content

Main-class: com.myclass.MainClass

now create the jar file as follows

   jar -cmf manifest.mf yourjarfile.jar <your class file location>

Run this jar with the following command

    java -jar yourjarfile.jar

score 0 · Answer 4 · answered Oct 09 '12 at 13:31

0

Yes, use the -jar parameter:

java -jar MyProgram.jar

answered Oct 09 '12 at 13:31

Sjoerd

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Yep, but jar contains a lot of other java classes. – johnny-b-goode Oct 09 '12 at 13:32
Lets say its not a "MyProgram.jar" but "AllMyPrograms.jar" and i need to run "MyFirstProgram.java". – johnny-b-goode Oct 09 '12 at 13:33

score 0 · Answer 5 · answered Oct 09 '12 at 13:34

0

you can extract the specific class file by doing:

jar xf MyProgram.jar theclass.class

it will end up in your current directory

then just run the classfile

java theclass

answered Oct 09 '12 at 13:34

dunn less

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Is it possible to run without extraction? – johnny-b-goode Oct 09 '12 at 13:36
try java -jar MyProgram.jar .theclass – dunn less Oct 09 '12 at 13:40

How to run java class from .jar archive?

5 Answers5