(Quick Reference)
                clearErrors
Purpose
Resets the list of errors on a domain class.  This may be useful if a domain class contains errors because of binding problems or validation problems.  The errors may be corrected programatically.  Validation may continue to fail unless the errors are cleared.
Examples
def b = new Book(title: "The Shining")
b.validate()
if (b.hasErrors()) {    // clear the list of errors
    b.clearErrors()    // fix the validation issues
    b.author = "Stephen King"    // re-validate
    b.validate()
}