Groovy is an agile dynamic language for the Java Platform with many features that inspired languages like Python, Ruby and Smalltalk, making them available to Java developers using a Java-like syntax.

The Grails project.

The Grails plugins project is a SVN repo and JIRA setup to support the development of plugins for the Grails project (http://grails.org)

A build system that uses Groovy as the scripting language and Ant tasks and Maven plugins as the mechanisms for creating actions. It can be thought of as Ant/Maven without the XML but very Groovy.

Gradle is a build system written in Groovy. It uses Groovy also as the language for its build scripts. It has powerful multi-project build support. It has a layer on top of Ivy that provides a build-by-convention integration for Ivy. It gives you always the choice between the flexibility of Ant and the convenience of a build-by-convention behavior.