Groovy is supported natively in NetBeans IDE from NetBeans IDE 6.5 onwards. That means that you do NOT need to install any plugins of any kind if you want to code in Groovy in NetBeans IDE.
The Groovy editor is a standard part of the "Java" distribution, i.e., the distribution aimed at Web development. Also included in that distribution is support for Grails. Click here to download the "Java" distribution, 6.5 or above:
Note: The Groovy editor is not part of the Java SE distribution of NetBeans IDE, since that distribution is meant to be as small as possible. You are therefore advised to use the "Java" distribution instead, if you want to use Groovy. You will then, optionally, also be able to use Grails.
Here is described how to use Groovy in NetBeans IDE:
Here's a screenshot showing a specific icon for Groovy files in the IDE:
Here is described how to use Grails in NetBeans IDE:
You can create complete Grails applications, running all the Grails commands from the IDE.
For Grails domain and controller classes, code completion in the Groovy editor from NetBeans IDE 6.7 onwards provides the names of dynamic methods:
Work is being done on Griffon support for NetBeans IDE too. A pre-alpha version of the support is available here:
For example, the Griffon plugin lets you call 'griffon create-app' from in the IDE, via the Griffon Application template: