Java for the web
I downloaded the latest JRE called "Java SE 6 Update 32" from Oracle. Some websites used Java. That was why I had to use it.
For example, this educational site used Java.
To install Java, I typed:
chmod +x jre-6u32-linux-i586.bin
I got the directory of "jre1.6.0_32".
To make Firefox and SeaMonkey use Java, I typed
ln -s '/path/To/Java/jre1.6.0_32/lib/i386/libnpjp2.so'
That was all.
Verifying the Java plugin
I typed about:plugins in the address bar of the browser to verify that the plugin was properly installed.
Using OpenJDK instead?
For advanced users, it was still necessary to use Oracle's JRE since OpenJDK might NOT work for most or all websites.