Best practice to pass a Domain Class between Grails (Groovy) and Java classes?
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I have a Grails service that calls a utility class written in Java. The Java utility class would need to use and manipulate the Domain Classes written in Grails, which are passed into it. Also eventually, the output needs to be a Domain Class in Grails and not a java object.

So basically:
Grails Domain Class input -> manipulated by Java utility class -> Grails Domain Class output to Grails Service and forward to Controller.

What would be the best practice to handle the above? Should I write identical value objects in Java? I guess I cannot manipulate the Grails Domain Classes directly within the Java class?