comparator.constructors[0].newInstance([domainClass] in grails 3

To construct an instance using the comparator.constructors[0].newInstance([domainClass]) method in Grails 3, you can follow the steps below:

1. Retrieve the comparator object.
2. Access the constructors property of the comparator object.
3. Use the index [0] to get the first constructor from the constructors array.
4. Invoke the newInstance method on the selected constructor.
5. Pass the [domainClass] as an argument to the newInstance method.

These steps will allow you to construct an instance using the comparator.constructors[0].newInstance([domainClass]) method in Grails 3.