Before you ask why your Java applications don’t work, or why your applet doesn’t initialize in Firefox, Seamonkey or Whatever browser you use do you know what version of Java you are using?
“Yes, I installed the JRE 1.6.0_XX”,
Thats nice, but is it running? Now, it may seem as obvious as “Is your computer on?” to some, but to others and I admit myself it isn’t always that obvious. I had installed the Java Runtime /JDK and tested my firefox. Programs worked from the command line, java -version provided me the correct Java version, but why were my applets failing to load?
The firefox plugin is the answer. Open up about:plugins in firefox and take a look at the Java providers. If you don’t see the Java(TM) plugin there then there is a problem. Refer to the Correct Java documentation on how to get this corrected. Basically you symlink a file and disable the other Java providers.