Fix for GRAILS-4621: Validation errors not read from message bundle for POJO domain entities

[beskow]

Validation error messages are not read from message bundle when using POJO (EJB3-annotated) domain entities, since their validator lacks a messageSource reference. Hence all validation error messages always use the default messages in english. In a I18n-enabled application, that is not acceptable.

This commit fixes the problem by

• modifying GrailsHibernateDomainClass to have a grailsApplication injected in its constructor, and use it to retrieve a messageSource
• modifying GrailsHibernateUtils to pass the grailsApplication instance to GrailsHibernateDomainClasses

In JpaMappedDomainTests, a test is added to verify that GrailsHibernateDomainClass' verifier has a messageSource.

In order for the unit tests in JpaMappedDomainTests to run clean, the AbstractGrailsHibernateTests is fixed to correctly set the mainContext property of the grailsApplication.

[graemerocher]

Could you update:

MessageSource messageSource = (MessageSource) application.getMainContext().getBean("messageSource");

To be:

MessageSource messageSource = application.getMainContext().getBean(MessageSource.class);

Which is better as it doesn't depend on the bean name.

[beskow]

Good point, Graeme. Updated and pushed as 601b5cf.

[graemerocher]

Applied. Thanks.