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Thread: How to create jar file from eclipse?

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    Default How to create jar file from eclipse?

    Hi,
    I need to create a JAR file of my java project. In my project I have added 3 additional jar files - jython-2.5.4-rc1.jar,netty-3.9.0.Final.jar and commons-codec-1.9.jar. I have created JAR file of my project from Eclipse. But when I try to run that jar file from command promt (java -jar myjar.jar) I get NoClassFoundException for one of my additional jar files. Any idea why I am getting this error.

    exception.jpg


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    Default Re: How to create jar file from eclipse?

    What is in the jar that you create? Is that class in there? Are any classes from the library jars in there?

    Eclipse has options to include library jars inside a runnable jar. Make sure you select them, otherwise you'll have to add the library jars to the classpath whenever you run it.
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    Default Re: How to create jar file from eclipse?

    options to include library jars inside a runnable jar.
    Does that mean there is a classloader that can read classes from a jar file that is inside of another jar file?
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How to create jar file from eclipse?

    In my project there are two java classes which use other classes from external jars. This is how I have created my jar file in eclipse-
    jar1.jpg
    jar2.jpg
    jar3.jpg

    Everything seems fine but I am getting that error message when I run it from command promt.

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    Default Re: How to create jar file from eclipse?

    Where is the missing class file? Do you want all the classes merged into a single jar file or can some classes be kept in other jar files that are referenced by an entry in the Manifest file?

    NOTE: You can ignore most of this. I don't know how to use eclipse.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How to create jar file from eclipse?

    Quote Originally Posted by Norm View Post
    Does that mean there is a classloader that can read classes from a jar file that is inside of another jar file?
    Sorta. You can either extract the .class files from the library jars into the runnable jar, or add the library jar files themselves along with classes that allow loading from them, all inside the runnable jar. More info here: eclipse - What is the difference between runnable jar library handling options? - Stack Overflow

    --- Update ---

    OP, you want to be exporting a *runnable* jar file.
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    Default Re: How to create jar file from eclipse?

    My two java files and three external jars are there. So what did you mean by the missing class file?

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    Default Re: How to create jar file from eclipse?

    Quote Originally Posted by shoharb.uddin View Post
    My two java files and three external jars are there. So what did you mean by the missing class file?
    We're simply referring to the error.

    Just adding the jars isn't enough. You need to add the classes that handle loading from the library jars. Eclipse does this automatically when you export as a RUNNABLE jar. That's a different option in the export menu.
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    Default Re: How to create jar file from eclipse?

    I get NoClassFoundException
    I was calling the class that was not found the missing class.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: How to create jar file from eclipse?

    ok. so far i have tried only jar not runnable jar. let me try it now and then get back to you.

    --- Update ---

    It works after creating the runnable jar file instead of creating the simple jar file.
    Thank You very much.

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