Custom validator always produce the same validation error message

When you implement your own Validator class to be used with ValidateWith annotation, the error message can't be customized through getErrorMessageKey() method. 

The problem is the message used in the following code is hardcoded instead of calling same validator's method:

https://github.com/playframework/playframework/blob/master/framework/src/play-java/src/main/java/play/data/validation/Constraints.java#L498