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Thread: Could not find main class error

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    Default Could not find main class error

    I currently use Eclipse to maintain our Java application. I recently upgraded from Java 6 to Java 7. I updated my Eclipse projects to use the Java 7 .jar files. I can run the application from Eclipse via the Run Configuration. I can also run the Ant build and it completes successfully. When I install the application on my desktop, I receive the "Java Virtual Machine Launcher: Could not find main class..." error. My CLASSPATH is set to ".". I've searched for a resolution for the past 2 weeks without any luck. Any help is much appreciated.

    Thanks,

    Keith Shaffer


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    Super Moderator Norm's Avatar
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    Default Re: Could not find main class error

    When I install the application on my desktop
    Can you explain what "install" means? A properly constructed jar file should work from any folder.
    Is this a problem with using your IDE to build a jar file?

    For debug info: Open a command prompt window, CD to the folder with the jar file and enter:
    java -jar THEJARFILENAME.jar

    copy the full contents of the command prompt window and paste it here.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Could not find main class error

    When I run the Ant build, it creates an executable installer. For example: Installer.exe. It writes the installer to the correct mapping location that I have setup within Eclipse. I then go to the location and run the install executable. This executable writes the application executable, XXXX.exe to the correct location and also creates a shortcut on the desktop. When I double click on the desktop icon, I receive the error.

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    Default Re: Could not find main class error

    Sorry, I've never executed a java program from an .exe. I've always created jar files.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Could not find main class error

    Norm, I've only run the application from the .exe. If I were to navigate to the location of the .jar file that holds the main class and execute the following: java -jar BOLO-UI.jar I receive the following error:


    C:\Program Files (x86)\BOLO by P2 Energy Solutions\BOLO UI Development 13.0.0.1\
    bololib>java -jar BOLO-UI.jar
    Exception in thread "main" java.lang.NoClassDefFoundError: com/jidesoft/action/D
    efaultDockableBarHolder
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java :800)
    at java.security.SecureClassLoader.defineClass(Secure ClassLoader.java:14
    2)
    at java.net.URLClassLoader.defineClass(URLClassLoader .java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader. java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java: 361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java: 355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.j ava:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:4 25)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:3 58)
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.ja va:2570)
    at java.lang.Class.getMethod0(Class.java:2813)
    at java.lang.Class.getMethod(Class.java:1663)
    at sun.launcher.LauncherHelper.getMainMethod(Launcher Helper.java:494)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Launc herHelper.java:486)

    Caused by: java.lang.ClassNotFoundException: com.jidesoft.action.DefaultDockable
    BarHolder
    at java.net.URLClassLoader$1.run(URLClassLoader.java: 366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java: 355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.j ava:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:4 25)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:3 58)
    ... 18 more

    C:\Program Files (x86)\BOLO by P2 Energy Solutions\BOLO UI Development 13.0.0.1\
    bololib>

    The BOLO-UI.jar file has the main class in it.

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    Default Re: Could not find main class error

    Exception in thread "main" java.lang.NoClassDefFoundError: com/jidesoft/action/DefaultDockableBarHolder
    Is the: com.jidesoft.action.DefaultDockableBarHolder
    class in the jar file?

    This doesn't sound like a problem with a java source. It looks like a problem with configuring the build tools.
    If you don't understand my answer, don't ignore it, ask a question.

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