If you have upgraded your browser to Lion, you have probably noticed that Java doesn’t run in your browser anymore. From what I can tell, it doesn’t run in any browser. It’s a pretty easy fix.
Open terminal and type:
/Applications/Utilities/Java\ Preferences.app/Contents/MacOS/Java\ Preferences
This will downloading some files and do an installation. Once it is complete, the Java Preferences will appear. In Java preferences, check the box that says “Enable applet plug-in and Web Start applications.”
Once you do this, Java should be working in your browsers.