You use the Advanced tab to specify the Java Runtime Environment (JRE) used by Java Plug-in. The Control Panel automatically detects all versions of the JDKs and JREs installed on your machine, and displays these in the dropdown list box.
Sun does not support the use of any JRE less than 1.2.1_03 with Java Plug-in 1.2.
If you use a JRE other than the default, you must specify the JRE path using an environment variable.