I can run the Java test page here in firefox, and it works fine. When I open it in chromium, it just stays white, and no "java" instance is started. Minecraft works fine. The screen shot was taken whil openjdk-6 was installed.
I have tried the following:
*Clearing Chromium preferences data (rm -rfv ~/.config/chromium)
*Purging and re installing all java-related packages, including the icedtea plugin.
*Using Openjdk-7 and 6
I am currently running Chromium 18 (the latest update)