Validator Exception Spring Integration: returning an error message in validator

Does anybody has an idea about how I can return an error message. I am trying to return an specific xml error message in my validator. This is my code:

 @Override
    public void validate(Object target, Errors errors) {
        try {
            ValidationClassUtil.validateDocument(new String((byte[]) target), xmlVersionEnum);
            (//should the error be returned here when I send an invalid xml file over http?)
        } catch (Exception exc) {
            errors.reject(errorCode);
        }
    }