March 21, 2010 - kenshinjeff

Troubleshooting a BlackBerry with JL_Cmder JVM Error 102

Recently, I had the chance to play with a BlackBerry. For most telcos, I believe you can do a one to one exchange, but what if you need to backup your data and it’s 3am at night? You can attempt to fix it yourself before deciding to wipe it. Using this method, it is possible to access your BlackBerry while the screen shows the dreaded JVM Error 102 / infinite reset screen.

Install the BlackBerry Desktop application if you have not done so, you should have an installation cd which comes with your BlackBerry or you can download it from here.

Download the JL_Cmder JavaLoader Utility from blackberryfreaks.

In case you were wondering, I believe, most, if not all BlackBerry applications are running on java. When you download a BlackBerry application from a website, it actually downloads a text file called “application_name.jad” which instructs the BlackBerry to download and install the various installation files onto your BlackBerry. If not, let me know, I’ll tinker with it when I have the opportunity to do so : x

If you open the .jad file with a text editor, you will find that it contains the following instructions/configurations:

  • SHA Keys for encryption/checksums
  • Filesize
  • Packaged file name (application_name.jar)
  • Descriptions
  • COD-URL (List of files to download – application.cod, application-1.cod, application-2.cod, etc, etc.)
  • COD-Size (List of the corresponding file sizes)
  • Module-name of application
  • etc, etc.

Turn on your BlackBerry, plug it to your computer with your USB cable. Run JL_Cmder.cmd which you got from At this point, you should be able to see a screen similar to this:


For debugging purposes, you can select eventlog (option 2). This will dump the eventlog from the phone, onto notepad for you to view through. Look through the last few lines where it says “error” or “failed”.

In most cases, deleting the offending files will enable you to narrow down which applications are causing you problems. Do note that one application may consist of several cod files to delete. You will need to access the cmd.exe from windows, navigate to where you unzipped the JL_Cmder, and run the following command:

javaloader.exe -u erase -f FILENAME

where FILENAME is the name of the .cod file

So, it could look like this:

javaloader.exe -u erase -f application.cod
javaloader.exe -u erase -f application-1.cod
javaloader.exe -u erase -f application-2.cod

At this point, you should quit JL_Cmder, try to reboot your phone, and pray that it works. If it does, do remember to use the BlackBerry Desktop application to make a backup. Just in case. *wink*

If it doesn’t you have the option of wiping your BlackBerry (option 4), or resettofactory (option 5).

geeky stuff / HOW-TOS blackberry / JL_Cmder /

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