@Temporal annotation must be specified for persistent fields or properties of type java.util.Date and java.util.Calendar.

This annotation is defined as:

package javax.persistence;
  ........
public @interface Temporal {
   TemporalType value();
}

where TemporalType enum is defined as:

package javax.persistence;
...
public enum TemporalType {
     DATE,//Map as java.sql.Date
     TIME,//Map as java.sql.Time
     TIMESTAMP// Map as java.sql.Timestamp
}

Since java.util.Date and java.util.Calendar are not compatible to the standard SQL date types (DATE, TIME, TIMESTAMP), we must use @Temporal on these types and should specify the TemporalType for intended conversion.

Example

Entity

@Entity
public class ScheduledEvent {
    @Id
    @GeneratedValue
    private long id;
    private String eventName;

    @Temporal(TemporalType.DATE)
    private Date date;

    @Temporal(TemporalType.TIME)
    private Date start;

    @Temporal(TemporalType.TIME)
    private Date end;

    @Temporal(TemporalType.TIMESTAMP)
    private Date eventCreated;
    .............
}

public class ExampleMain {
    private static EntityManagerFactory entityManagerFactory =
            Persistence.createEntityManagerFactory("example-unit");

    public static void main(String[] args) {
        try {
            persistEvent();
            findEvent();
            nativeQuery("select CONCAT('start= ', e.start, '\nend= ', e.end, '\ndate= ', e.date,"
                     +"'\neventCreated= ', e.eventCreated)"
                    + " from ScheduledEvent e");
        } finally {
            entityManagerFactory.close();
        }
    }

    private static void persistEvent() {
        ScheduledEvent scheduledEvent = ScheduledEvent.create("Test event",
                LocalDate.of(2018, 6, 1),
                LocalTime.of(9, 30, 45),
                LocalTime.of(11, 45, 30));
        System.out.println("-- persisting entity --");
        System.out.println(scheduledEvent);
        EntityManager em = entityManagerFactory.createEntityManager();
        em.getTransaction().begin();
        em.persist(scheduledEvent);
        em.getTransaction().commit();
        em.close();
    }

    private static void findEvent() {
        System.out.println("-- finding entity --");
        EntityManager em = entityManagerFactory.createEntityManager();
        ScheduledEvent scheduledEvent = em.find(ScheduledEvent.class, 1L);
        System.out.println(scheduledEvent);
        em.close();
    }

    public static void nativeQuery(String s) {
        EntityManager em = entityManagerFactory.createEntityManager();
        System.out.println("-- native query --");
        Query query = em.createNativeQuery(s);
        List list = query.getResultList();
        for (Object o : list) {
            if (o instanceof Object[]) {
                System.out.println(Arrays.toString((Object[]) o));
            } else {
                System.out.println(o);
            }
        }
        em.close();
    }
}

-- persisting entity --
ScheduledEvent{id=0, eventName='Test event', date=Fri Jun 01 00:00:00 CDT 2018, start=Wed Dec 31 09:30:45 CST 2, end=Wed Dec 31 11:45:30 CST 2, eventCreated=Sun Jun 10 21:01:58 CDT 2018}
-- finding entity --
ScheduledEvent{id=1, eventName='Test event', date=2018-06-01, start=09:30:45, end=11:45:30, eventCreated=2018-06-10 21:01:58.265}
-- native query --
start= 09:30:45
end= 11:45:30
date= 2018-06-01
eventCreated= 2018-06-10 21:01:58.265

Example Project

Dependencies and Technologies Used:

• h2 1.4.197: H2 Database Engine.
• hibernate-core 5.2.13.Final: The core O/RM functionality as provided by Hibernate.
  Implements javax.persistence:javax.persistence-api version 2.1
• JDK 1.8
• Maven 3.3.9