How can I get the default value of a parameter (method) in groovy at runtime?

How can I get the default value of a parameter (method) in groovy at runtime? Is there a possibility?

Aside from invoking the method without supplying the parameter and then inspecting the value that was passed in, not a practical one, no. You could write code that parses the .class file and the info is there, but I don't think there is anything in Groovy related that is going to help or be relevant.