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Thread: need help on jar files

  1. #1
    Junior Member
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    Jul 2010
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    Default need help on jar files

    ]hi 2 every1

    i made a simple swing application with some database connectivity in it. d whole prog ws typed in notepad++ nd executed from command prompt. it ws executing perfectly. fyn...
    nw i copied d whole code in netbeans nd tried to build to main project so as to get my .jar file of my coding. .jar file ws created successfully, bt when i tried 2 run it, it ws nt executing properly.
    fr eg, i hd a button in my application that displays all records present in d database. it displayed all records when i executed wid command prompt, bt when .jar file ws excecuted, no response ws made.
    plz help me to get out of dis prob

    thanx in advance

  2. #2
    Forum VIP
    Join Date
    Jul 2010
    Thanked 329 Times in 305 Posts

    Default Re: need help on jar files

    Check to make sure the manifest is correct. To do that, either open the jar in WinRAR or open it manually.

    To do this, go to Control Panel -> Folder Options -> View -> Uncheck "Hide Extensions for known file types". Then go to your jar, right click, rename, change the extension from .jar to .zip. You will get a confirmation, and click ok. Now you can open your jar.

    Do this regardless of how you opened it:
    Inside the jar should be a folder named "META-INF". Go into that folder, inside that folder should be a document called "MANIFEST.MF". Open that in Notepad. The Manifest should read something like:
    Manifest-Version: 1.0
    Created-By: 1.6.0_14 (Sun Microsystems Inc.)
    Main-Class: War2_0
    3 things to note here are:
    1) The "Main-Class:" variable should be the name of the class with the main in it (no extension).
    2) The "Class-Path:" variable referenses any external libraries you used. It is best to include your external libraries in the same location as your executable jar. That way the "Class-Path:" variable will just include the library names and not any paths.
    3) The blank line at the end of the MANIFEST. I dont know why it needs it, but it does.

  3. #3
    Super Moderator Norm's Avatar
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    May 2010
    Eastern Florida
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    Default Re: need help on jar files

    Cross posted at: need help on jar files - Java Forums

  4. The Following User Says Thank You to Norm For This Useful Post:

    Darryl.Burke (July 14th, 2010)

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