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Thread: Can anyone help with my code please?? (Reading the Registry)

  1. #1
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    Default Can anyone help with my code please?? (Reading the Registry)

    Hi, im trying to get this to read the registry by reading the contents of a folder, turning it in to an array then displaying the contents. When i compile it works fine with no errors, however when i run it once compiled, it give me the error
    Exception in thread "main" java.lang.NullPointerException
    at USBDevices.main(USBDevices.java:19)
    I've tried putting throw IOException in to, which compiles fine but still gives me the same error message.

    Can anyone help me with this?

    Thanks

    import java.io.*;
    import java.util.*;
     
    public class USBDevices
    {
     
       public static void main(String[] args)
       {
     
       	// This retrieves the files from the registry and inserting it in to an array called file
     
          java.io.File listroot = new java.io.File("\"HKLM\\SYSTEM\\CurrentControlSet\\Enum\\USBSTOR\"");
          java.io.File[] files = listroot.listFiles();
     
          System.out.println("USB Registry Entries:");
     
         // This opens the array called and displays the results
     
          for (java.io.File file : files)
     
            {
             if (file.isDirectory())
                continue;
             System.out.println(file.getPath());
            }
     
     
     
        }
    }


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    Super Moderator Norm's Avatar
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    Default Re: Can anyone help with my code please?? (Reading the Registry)

    gives me the same error message.
    What variable has a null value at line 19?
    When you find the variable, you need to backtrack in the code to see why that variable does not have a valid value.

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    Default Re: Can anyone help with my code please?? (Reading the Registry)

    i dont get what i need to do. when i change the folder to read to a C:\\ folder it works fine but i just dont understand why it doesnt work for the registry folder.

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    Super Moderator Norm's Avatar
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    Default Re: Can anyone help with my code please?? (Reading the Registry)

    What variable has the null value? Why is its value null?

    Why do you think this is a valid path to a file:
    "\"HKLM\\SYSTEM\\CurrentControlSet\\Enum\\USBSTOR\ ""

    Print out the value of the File class's exists() method to see if the file exists.

    Java doesn't support reading the Windows registry (other than a special place for its data)
    You will need to use a Windows program to read the registry and print out a report that you can get using a Runtime and Process class.
    Last edited by Norm; February 9th, 2012 at 11:32 AM.

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