According to the JPA spec, support is provided for the five temporal types:
java.sql.Date, java.sql.Time, java.sql.Timestamp, java.util.Date, java.util.Calendar.

However, what about GregorianCalendar - this class inherits from java.util.Calendar?

I wrote some test code and Hibernate supports GregorianCalender if the temporal annotation is used at field level.

For example:

@Temporal(TemporalType.DATE)
private GregorianCalendar dateOfBirth = null;

This works.

However, if the annotation is at method level, for example,

@Temporal(TemporalType.DATE)
public GregorianCalendar getDateOfBirth() {
return dateOfBirth;
}

hibernate will throw an annotation exception at start up.

Failed to invoke suite():javax.persistence.PersistenceException: org.hibernate.AnnotationException: @Temporal should be set on a java.util.Date or java.util.Calendar property: Person.dateOfBirth

Is this a bug?
Comments welcomed

You probably left your @id annotation on field