Question

Is it possible for us to find what are the primary key fields for a Hibernate entity programmatically (similar to JPA’s PersistenceUnitUtil)?

Answer 1

SessionFactory provides an method called getClassMetadata() to get the meta-data object for a class (i.e. ClassMetadata)

To get the name of the identifier properties of an entity , use ClassMetadata.getIdentifierPropertyName()

ClassMetadata employeeMeta =  sessionFactory.getClassMetadata(Employee.class);
System.out.println("Name of the identifier property of the employee entity :" + employeeMeta .getIdentifierPropertyName());

To get the value of the identifier properties for an managed entity instance , use ClassMetadata.getIdentifier(Object entity, SessionImplementor session)

For example :
Suppose you have a managed entity instance that is loaded from a session :

List<Employee> employeeList = (List<Employee>)session.createQuery("from Employee where gender ='F'").list();
ClassMetadata employeeMeta = session.getSessionFactory().getClassMetadata(Employee.class);
for (Employee employee : employeeList ) {
    System.out.println("Value of the Primary key:" + employeeMeta.getIdentifier(employee , session) );
}