Introduction
Ant is the predominant build environment for Java projects. Groovy is a leading Scripting language for the JVM. The good news is that you can use them together easily and with many benefits.
Existing Ant Users (Java Projects): If you are already familiar with using Ant with a traditional build.xml file, then you can continue to do so with almost no changes. If you want you can begin to use the Groovy Ant Task to bring the full power of a scripting language to your build scripts.
Existing Ant Users (Groovy or mixed Groovy/Java Projects): If you wish to pre-compile your Groovy scripts as part of your build process (it can help catch syntactic errors earlier if you do) then you need to know about the Groovyc ant task. You will find it almost identical to the javac task which you are probably already familiar with.
Existing Groovy Users: You probably want to consider how you can use AntBuilder to leverage the many available Ant tasks directly in your code using a DSL-style notation. You can leverage Ant Libraries in the same way.
Further Information
A few articles related to this topic: