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Thread: Package confusion

  1. #1
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    Default Package confusion

    We have been supplied with a bunch of example code files for an assignment. Each file has
    package FabricCuts
    at the top. I can't get any of the files to run if I have the package stuff at the top, but if I remove the line from each file they run fine.

    What I've tried:
    1. Creating a new directory FabricCuts and moving all files inside.

    Here is the error I see with a bit of context.

    > ls
    Garment.java          GarmentFile.java      GarmentFileTest.java  Piece.java            PieceTest1.java       TextFile.java         TextFileTest.java
    > javac PieceTest1.java Piece.java 
    > java PieceTest1
    Exception in thread "main" java.lang.NoClassDefFoundError: PieceTest1 (wrong name: FabricCuts/PieceTest1)
            at java.lang.ClassLoader.defineClass1(Native Method)
            at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
            at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
            at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
            at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
            at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
            at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
            at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
    >

    As I said everything works fine if I remove the package line from the top of each file, but I'd rather know how it is supposed to work.

    Thanks.


  2. #2
    Administrator copeg's Avatar
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    Default Re: Package confusion

    If you have not yet, see Creating and Using Packages (The Java™ Tutorials > Learning the Java Language > Packages)
    In elementary terms, packages are basically directories. How are you trying to compile/run the classes? Command line? IDE?

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    Default Re: Package confusion

    Thanks copeg, I did stumble across that link, that's what tipped me off about creating a folder.

    I'm using the command line to compile and run classes. The commands I used (javac, java) can be seen in my original post.

    If it's relevent I'm using the diablo-jdk package on FreeBSD 8-STABLE

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    Default Re: Package confusion

    Sorry, missed the command-line text in your original post. Try compiling and running from the root of the package. If you have a folder named 'FabricCuts', and all .java files of the FabricCuts package are in that folder, go one directory up and type 'javac FabricCuts/myclass.java Same goes for running it.

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    Default Re: Package confusion

    Ah ha. Thank you very much.

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