Accessing i18n Messages from exception (validation errors) in Grails in a Service

To access your message, inject the MessageSource into your service:
def messageSource  

And to get the error messages from exception based on your i18n properties file, use the following code block in your service:
 

def messageSource;

def printAllMessage(Exception ex) {
    ex.errors.allErrors.eachWithIndex { ObjectError objectError, Integer index ->
        println "Error #${index}: " + messageSource.getMessage(objectError, Locale.default);
    }
}

Will output something like this based on you i18n messages.properties file:

Error #0: Property [accountId] cannot be null
Error #1: Property [displayName] cannot be null
Error #2: Property [emailAddress] with value [pritom@bitmascot.com] must be unique

If your i18n file contains something like:

default.null.message=Property [{0}] cannot be null
default.not.unique.message=Property [{0}] with value [{2}] must be unique