This tutorial requires that you have Java 1.2 (or later) and Relaxer 1.0RC installed on your computer. You must also have the Java API for XML Processing (JAXP) installed. You can install JAXP separately or you can install a version of Java that comes with JAXP, such as Java 2 version 1.4 (or higher).
You probably already have Java and JAXP installed on your system; if you don't, you can go to the Sun site to /download/ the latest distribution. Installation instructions are available on or from the Java site.
You can use Relaxer on any platform that supports Java; however, the examples shown in this tutorial have only been tested on Windows XP Professional using Java 2 v1.4.