Web-based Java games cause computer lockup/crash

Hey there. Sometimes java applets and other data in your browser cache may cause this type of problem. The order of problem resolution I would try would be the following:

1. Delete all temporary internet files and cache: Firefox.. Edit... Preferences... Privacy... Private Data... Settings button. Check mark everything except your passwords. Then go ahead and clear the data. Close the browser and relaunch your site again.

2. If the above doesn't help, perhaps there is an issue with your local browser profile. Close your browser, and from a command line, move the .mozilla folder to a different name. When you launch firefox again, it will be as if you are launching it again for the first time:

$ cd ~/
$ mv .mozilla .mozilla.backup

3. If that doesn't work, verify your java version information:
$ java -version

and then verify your java plugin information from firefox address bar:
about:plugin

You can try making sure you only have one version of the java plugin, and alternating between java5 and java6 from synaptic.

4. The website may have recently changed the java applet that may be incompatible with your browser plugin. In which case, if the above steps don't help... you can try running the exact same applet on a different Ubuntu machine to compare results.

Hope this helps you get started in troubleshooting the issue.

i dont store any temporary internet files on my computer, so the first step doesnt really apply, but i tried it anyway. moving the mozilla folder did allow me to run the apps, but now the sound for the apps is messed up. also, the problem isnt website specific, because i tried it with a few other sites with the same results.

when i tried to verify the java version, it gave me this output:
andrew@MYLINUXCOMP:~$ java -version
The program 'java' can be found in the following packages:
 * j2re1.4
 * kaffe
 * cacao
 * java-gcj-compat
 * gij-4.1
 * jamvm
 * gij-4.2
 * sablevm
Try: sudo apt-get install <selected package>
bash: java: command not found
andrew@MYLINUXCOMP:~$

and the about:plugin did not work. it said the url is invalid and address cannot be loaded

Many apologies. The URL is "about:plugins".

Also, let's make sure java is installed. You're output for "java -version" states that it cannot be found.

$ sudo apt-get install sun-java6-bin sun-java6-plugin sun-java6-fonts

ok, when i query firefox, heres what it gave me for my java :

Java(TM) Plug-in 1.6.0_01-b06

    File name: libjavaplugin_oji.so
    Java(TM) Plug-in 1.6.0_01

MIME Type Description Suffixes Enabled
application/x-java-vm Java Yes
application/x-java-applet Java Yes
application/x-java-applet;version=1.1 Java Yes
application/x-java-applet;version=1.1.1 Java Yes
application/x-java-applet;version=1.1.2 Java Yes
application/x-java-applet;version=1.1.3 Java Yes
application/x-java-applet;version=1.2 Java Yes
application/x-java-applet;version=1.2.1 Java Yes
application/x-java-applet;version=1.2.2 Java Yes
application/x-java-applet;version=1.3 Java Yes
application/x-java-applet;version=1.3.1 Java Yes
application/x-java-applet;version=1.4 Java Yes
application/x-java-applet;version=1.4.1 Java Yes
application/x-java-applet;version=1.4.2 Java Yes
application/x-java-applet;version=1.5 Java Yes
application/x-java-applet;version=1.6 Java Yes
application/x-java-applet;jpi-version=1.6.0_01 Java Yes
application/x-java-bean Java Yes
application/x-java-bean;version=1.1 Java Yes
application/x-java-bean;version=1.1.1 Java Yes
application/x-java-bean;version=1.1.2 Java Yes
application/x-java-bean;version=1.1.3 Java Yes
application/x-java-bean;version=1.2 Java Yes
application/x-java-bean;version=1.2.1 Java Yes
application/x-java-bean;version=1.2.2 Java Yes
application/x-java-bean;version=1.3 Java Yes
application/x-java-bean;version=1.3.1 Java Yes
application/x-java-bean;version=1.4 Java Yes
application/x-java-bean;version=1.4.1 Java Yes
application/x-java-bean;version=1.4.2 Java Yes
application/x-java-bean;version=1.5 Java Yes
application/x-java-bean;version=1.6 Java Yes
application/x-java-bean;jpi-version=1.6.0_01 Java Yes

this means i must uninstall this version first, right?

No this is fine. It means you have correctly installed java for your machine and browser. To make sure Java is working, visit the following URL:

http://www.java.com/en/download/installed.jsp

Click the verify link, and it will tell you if all is well.

If the particular site still gives you problems, perhaps you can post it here, and see if anyone else can reproduce the issue.

acording to the above link, all is well, but the sound is still choppy... im going to try uninstalling the java and reinstalling it, and seeing if that helps.

i dont think the problem was site specific, but ill test around and see if i can make it happen anywhere else, and post back if i can. the first site it happened at was runescape.com though

i dont know if this is related or not, but now my computer is now also locking up when the screensaver comes on. i left the thing alone for about 3 hours this morning because i had a download i needed to finish, and when i came back the whole thing was frozen, and i had to restart. it has happened 3 times since then, but once i was able to switch to a ctrl+alt command line, and when i switched back to the gui, it had about 8 lines that all started with 'shutting down' something..the first said something like 'shutting down gnome display manager'...sorry i cant remember exactly. i was distracted by the fact that i couldnt type anything, but i could switch between the command lines. i havent been able to reproduce that yet...but ill try again

ok, problem is no longer present, i uninstalled and reinstalled the java package, and everything was all better. thanks for the help!