Anthony Goubard is a freelance Senior Software Engineer from Amsterdam. He has developed in Java since 1995. He has developed many softwares available at and is the main developer of the Web Services framework XINS. Anthony is a DZone MVB and is not an employee of DZone and has posted 33 posts at DZone. You can read more from them at their website. View Full User Profile

Java, JavaFX and Temporary Files

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Here is another angle on Java under the hood: "Temporary" files. Yes, Java and JavaFX create a bunch of temporary files (some of them being more permanent than others).Here is a view of some of them (my OS is Windows XP):

  • {user.home}\Local Settings\Temp\jusched.log
    This file contains the logs of the Java Update Scheduler. It's used to update Java and JavaFX. It seems to check quite often. For example my file contains:
    Thu Apr 02 09:08:13 2009
    :: Started JavaFX Update process Command:C:\Program Files\Java\jre6\bin\javaws.exe  -silent -import -reverse -javafxau ""
    Return:1 Error:0
    Fri Apr 03 09:07:08 2009
    :: Started JavaFX Update process Command:C:\Program Files\Java\jre6\bin\javaws.exe  -silent -import -reverse -javafxau ""
    Return:1 Error:0
  • {user.home}\Local Settings\Temp\java_install_reg.log
    Another Java log file. This one seems to be about JNI calls (done by the Java quickstart/updater?).
    Process start at 06/08/2009-17:49:51.
    == Start JNICALL Java_com_sun_deploy_panel_PlatformSpecificUtils_getJqsSettings ==
    == End JNICALL Java_com_sun_deploy_panel_PlatformSpecificUtils_getJqsSettings ==
    Process start at 06/10/2009-14:55:54.
    == Start JNICALL Java_com_sun_deploy_util_UpdateCheck_shouldPromptForAutoCheck ==
  • {user.home}\Local Settings\Temp\java_install_sp.log
    Another file created by the installer that contains information such as the locale and the default browser. What you can see is that depending on your country and your default browser, you get different "sponsors". Here are a few lines of the content:
    -- ShowYahoo -- Not a country in the country list
    -- ShowMSTB -- IE is NOT the default browser
    -- DetermineSponsor -- The preference order is: SP8;SP4
    -- DetermineSponsor -- NO sponsors found that have not already been offered
  • {user.home}\Local Settings\Temp\3f1c0c4.mst
    The Java 6 + JavaFX installer. This file hasn't been deleted at the end of the installation as expected.
  • {user.home}\Local Settings\Temp\jinstall.cfg
    XML file containing the Java updater options (where to download the update, the sponsors, ...). Here are a few lines from it:
  • {user.home}\Local Settings\Temp\jnlp-applet
    This directory contains empty files (maybe used as lock) and dll (like JOGL). Maybe created by JavaFX applets that use JOGL.
  • {user.home}\Local Settings\Temp\
    Similar to jnlp-applet (maybe from another JavaFX version).
  • {user.home}\.javafxcache\images
    An empty directory
  • {user.home}\javafx-sdk\1.1
    It contains 1 log file, a few images and small technical files (but no SDK)
  • {user.home}\Local Settings\Temp\hsperfdata_{}
    Directory containing temporary 64.0KB unreadable files.
  • {user.home}\.java.policy
    This one contains:
    grant codeBase "file:/${user.home}/Application Data/Agency9/3DMapsK1/3DMapsK1/-" { permission; };
  • {user.home}\.javafx_eula_accepted
    An empty file
  • {user.home}\.javafx_ping_sent
    This one contains:
    1.1-internal jfxiu jfxic
    1.1.1 jfxiu jfxic
    1.2.0_b233 jfxiu
  • {user.home}\Application Data\Sun\Java
    It contains a Deployment directory used by Java Web Start, a few jre1.6.0_xx directories containing a small lzma.dll file and a few jdk1.6.0_xx directories containing the full JDK installer (75 MB per directory)
  • {user.home}\Application Data\[ManufacturerNonTM]\[ProductNameNonTM]\install
    It contains the JavaFX 1.1 SDK installer (42 MB)

Well, as you can see that's a lot of "temporary" files and I haven't counted the ones created by Java applications like NetBeans, Groovy and others.


Published at DZone with permission of Anthony Goubard, author and DZone MVB.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)



Richard Osbaldeston replied on Fri, 2009/09/04 - 6:43am

I noticed a couple the other day


Stupidly I right-clicked on one of ther and viewed with Notepad, unfortunatly left 'associate with' checked which promptly hid the filename as I also had 'hide known extensions' turned on and Windows took the whole filename as one big extension. Nice. Had to dip into regedit to fix that.

 Also seem to have a whole bunch of these:



Tim Boudreau replied on Sat, 2009/09/05 - 3:24pm in response to: Richard Osbaldeston

hs_err_pidxxxx.log - these would be indications of VM crashes.

Marissa Maples replied on Tue, 2010/11/23 - 2:19am

This addition is extremely welcome since transparency, while available on most platforms, was not available via the JColorChooser. Unfortunately most java GUI designers relied on the the chooser instead of creating their own which left you to hand code the transparency (assuming the tool was generating java code losing baby weight). This will be a boon for Netbeans users.

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