Appendix A. Installing Groovy
Groovy generates Java bytecodes that are interpreted by a Java virtual machine. This means you have to have Java installed in order to install Groovy. You need a full Java Development Kit (JDK), rather than a Java Runtime Environment (JRE). You only need the Standard Edition (SE) of Java, rather than the Enterprise Edition.
1 Just as an aside, when did the word business get deprecated in favor of the word enterprise? Is it a Star Trek thing? Does being an Enterprise Architect mean you design starships for a living? Are Enterprise Java Beans used when making coffee on a starship?
The official JDK for Java SE is available from Oracle at http://mng.bz/83Ct. At the time of this writing, the current version is Java SE 7u25 (Java 7, update 25), but Groovy works on any version of Java 1.5 and above.
Be sure to set an environment variable called JAVA_HOME to point to the installation directory. You also probably want to add the bin folder under JAVA_HOME to your path.
On Windows that will look like this: