Before you can start having fun programming in Java, you need to download the Java SE Development Kit. The JDK is the most important Java download you can make because once its installed, your computer will be able to understand and execute the programs you create.
Note: If you are a Mac user you do not need to download the JDK, instead read this guide on Java and the Mac OS X.
The JDK can be found on the Sun Microsystems Java downloads page.
