Posted by Tommaso Paba, email@example.com
on August 27, 2000 at 01:35
JRE is the Java Runtime Environment, required to run Java applications. JDK is the Java Developement Kit, used to develop java applications. JDK includes JRE, but only java programmers need it. You just need the JRE. Both are free and available from java.sun.com. Java, by the way, is a platform independent programming language.
The reason why it is required is that Java applications, to be platform independent, needs "something" beetwen the java executable and the underlying operating system (very condensed answer...).
Why didn't they use a platform-dependent language? They probably (and I hope so) want to port the WAP Toolkit under different platforms. Just consider that most of the web servers are based on Unix or Linux and many web developers prefer this operating system.