Let's start with a simple Java file and a simple Groovy file:
You can rename the field in the Java class:
This will perform the standard Java refactoring on all Java classes in your projects. Additionally, the refactoring will be performed on your groovy classes. If there are any ambiguous references to the Java field, the following dialog will open up allowing you to choose which references should be refactored:
And the result is what you would expect:
The refactoring can be initiated from the Groovy side as well:
As you can see, extract method an inline method are two other refactorings supported in Groovy code.
This functionality is currently available in the latest snapshot build of Groovy-Eclipse for Eclipse 3.5, available from the following update site:
Please send any questions or problems to the mailing list. We're happy to help. Enjoy!