For anybody wanting answers regarding Java, you really should start over at http://java.sun.com/
Java is a language for applications, like games and business stuff, all kinds of purpose
Java is comprised of different parts
It is an amazing technology that offers great solutions for business
It is broken up into different packages according to how you would use it
Java is installed, almost blindly to us, and incorporated into many websites where we are completely unaware of exactly how it affects us
Java is available to developers, incl. extra tools
Java is available to Enterprises with an independent platform so that the site and security of it are not compromised by the need for specific hardware or operating systems
I've got a link to a picture of an idea of how Java can be used, and the relativeness of the packages available http://java.sun.com/j2se/1.5.0/docs/index.html
Java is from Sun Microsystems
It is actually considered a "standard"
like ECMA is a standard for "C"
like how the W3C sets standards
Sun has produced Java as a set of standards available and describes the "whole" of Java as the Java Platform. You don't have to have the whole Java platform, just that which you need.
End users just need the Java Runtime Environment, for your internet browswer. the latest is available HERE
Java is on my list of things to learn. I gotta get through PHP first. Then we'll see, after maybe a few Linux lessons.