Why do I have to be outside the package's folder to properly execute the class file?












0















(Note: I know I am not using standard naming conventions here. The names are simply for the purpose of simplicity.)



I have a file called 'PackageTest.java'. It's sole purpose is to print a line to the console saying, "This works!". It belongs to a package named main. In my console I execute the command:



javac -d . PackageTest.java


This creates a new directory (folder) called main, which contains the class file named 'PackageTest.main'. I am CD'd into it's parent directory, and I execute the following command:



java main.PackageTest


And the console then reads:



This works!


So the file executed. That's good. Now I CD into the 'main' folder. I execute the command:



java main.PackageTest


Only to get the result:



Error: Could not find or load main class main.PackageTest

Caused by: java.lang.ClassNotFoundException: main.PackageTest


So I try this command:



java PackageTest


And now I get this error:



Error: Could not find or load main class PackageTest

Caused by: java.lang.NoClassDefFoundError: main/PackageTest (wrong name: 

PackageTest)


Why do I have to be outside of the directory to allow the file to execute?






java package javac







share|improve this question



























    0















    (Note: I know I am not using standard naming conventions here. The names are simply for the purpose of simplicity.)



    I have a file called 'PackageTest.java'. It's sole purpose is to print a line to the console saying, "This works!". It belongs to a package named main. In my console I execute the command:



    javac -d . PackageTest.java


    This creates a new directory (folder) called main, which contains the class file named 'PackageTest.main'. I am CD'd into it's parent directory, and I execute the following command:



    java main.PackageTest


    And the console then reads:



    This works!


    So the file executed. That's good. Now I CD into the 'main' folder. I execute the command:



    java main.PackageTest


    Only to get the result:



    Error: Could not find or load main class main.PackageTest
    
Caused by: java.lang.ClassNotFoundException: main.PackageTest


    So I try this command:



    java PackageTest


    And now I get this error:



    Error: Could not find or load main class PackageTest
    
Caused by: java.lang.NoClassDefFoundError: main/PackageTest (wrong name: 
    
PackageTest)


    Why do I have to be outside of the directory to allow the file to execute?






    java package javac







    share|improve this question

























      0












      0








      0








      (Note: I know I am not using standard naming conventions here. The names are simply for the purpose of simplicity.)



      I have a file called 'PackageTest.java'. It's sole purpose is to print a line to the console saying, "This works!". It belongs to a package named main. In my console I execute the command:



      javac -d . PackageTest.java


      This creates a new directory (folder) called main, which contains the class file named 'PackageTest.main'. I am CD'd into it's parent directory, and I execute the following command:



      java main.PackageTest


      And the console then reads:



      This works!


      So the file executed. That's good. Now I CD into the 'main' folder. I execute the command:



      java main.PackageTest


      Only to get the result:



      Error: Could not find or load main class main.PackageTest
      
Caused by: java.lang.ClassNotFoundException: main.PackageTest


      So I try this command:



      java PackageTest


      And now I get this error:



      Error: Could not find or load main class PackageTest
      
Caused by: java.lang.NoClassDefFoundError: main/PackageTest (wrong name: 
      
PackageTest)


      Why do I have to be outside of the directory to allow the file to execute?






      java package javac







      share|improve this question














      (Note: I know I am not using standard naming conventions here. The names are simply for the purpose of simplicity.)



      I have a file called 'PackageTest.java'. It's sole purpose is to print a line to the console saying, "This works!". It belongs to a package named main. In my console I execute the command:



      javac -d . PackageTest.java


      This creates a new directory (folder) called main, which contains the class file named 'PackageTest.main'. I am CD'd into it's parent directory, and I execute the following command:



      java main.PackageTest


      And the console then reads:



      This works!


      So the file executed. That's good. Now I CD into the 'main' folder. I execute the command:



      java main.PackageTest


      Only to get the result:



      Error: Could not find or load main class main.PackageTest
      
Caused by: java.lang.ClassNotFoundException: main.PackageTest


      So I try this command:



      java PackageTest


      And now I get this error:



      Error: Could not find or load main class PackageTest
      
Caused by: java.lang.NoClassDefFoundError: main/PackageTest (wrong name: 
      
PackageTest)


      Why do I have to be outside of the directory to allow the file to execute?






      java package javac




      java package javac






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 15 '18 at 4:40









      Caleb SuhyCaleb Suhy

      317




      317
























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          The package (and folder) are semantically meaningful. You can specify the classpath, if you use an absolute path you can move anywhere in your tree and still run the code. It's also possible to use a relative path. Like,



          java -cp .. main.PackageTest





          share|improve this answer























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            1 Answer
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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            4














            The package (and folder) are semantically meaningful. You can specify the classpath, if you use an absolute path you can move anywhere in your tree and still run the code. It's also possible to use a relative path. Like,



            java -cp .. main.PackageTest





            share|improve this answer




























              4














              The package (and folder) are semantically meaningful. You can specify the classpath, if you use an absolute path you can move anywhere in your tree and still run the code. It's also possible to use a relative path. Like,



              java -cp .. main.PackageTest





              share|improve this answer


























                4












                4








                4







                The package (and folder) are semantically meaningful. You can specify the classpath, if you use an absolute path you can move anywhere in your tree and still run the code. It's also possible to use a relative path. Like,



                java -cp .. main.PackageTest





                share|improve this answer













                The package (and folder) are semantically meaningful. You can specify the classpath, if you use an absolute path you can move anywhere in your tree and still run the code. It's also possible to use a relative path. Like,



                java -cp .. main.PackageTest






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 15 '18 at 4:45









                Elliott FrischElliott Frisch

                154k1393184




                154k1393184
































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