How to empty the Java cache on a Windows PC

Java is a software platform (previously part of Sun Microsystems, now part of Oracle) that allows you to run a lot of cool programs (like some of Yahoo!'s online games, as well as many business applications).  When you run an application that requires Java, it stores any necessary temporary files on your computer, in a Java cache.  Normally, there is no problem with this process, but occasionally you'll find a glitch.

You may try to run a Java program that's worked a million times before, but for some reason it just won't load, or it won't load past a certain point, or it won't let you update any information.  Often when this happens, clearing your Java cache will fix the problem.

When Java is installed on your computer, it creates an icon in the Control Panel so you can manage your Java settings and preferences.  To empty your Java cache, that is where you need to go.

Open your Control Panel, which can typically be found on the Start menu.  If you don't see it there, just type "control panel" in the Search bar if you're running Windows Vista or Windows 7.  In Windows XP, type "control" in the Run bar.  Once you've opened the Control Panel, double click the Java icon.  (It's the one that looks like a cup of coffee.)

Now you should be looking at the Java Control Panel.  Toward the bottom of the General tab is a section titled "Temporary Internet Files."  Click the Settings button.  To delete your temporary Java files, click "Delete Files," and then in the box that appears, make sure "Applications and Applets" and "Trace and Log Files" are both checked, and click OK.  The process of emptying the cache may take a couple of minutes.

Once you've emptied the Java cache, just restart your web browser or the program you were running, and hopefully your problem has been fixed.  If not, you may have a more serious issue -- see the program's help or troubleshooting guide for a possible solution.

There are several changes you can make to the way Java stores files on your computer.  If you don't want files stored at all, you can uncheck the box that says "Keep temporary files on my computer."  Be aware that doing this might prevent certain applications from running correctly.  You can also change the size and location of the Java cache, or turn on temporary file compression.  Compression will allow you to save some disk space, but it will take longer to access those files when they are needed.

(Originally posted on Helium.com, April 2010)