Load entity by id with SINGLE_TABLE inheritance

Question

I use Hibernate v.4 (inside Spring MVC). There are several inherited entities mapped on one table with SINGLE_TABLE strategy using DiscriminatorColumn:

@Entity
@DiscriminatorColumn
@DiscriminatorOptions(force = true)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public abstract class A {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    protected Long id;
    ...
}

@Entity
@DiscriminatorValue(value = "B")
public class B extends A {
   ...
}

@Entity
@DiscriminatorValue(value = "C")
public class C extends A {
   ...
}

Consider I have universal GUI interface for managing this entities, so in input (say in HttpServletRequest) I have only id of the object, but I don't know which type exactly is this object; that is why I can not specify exact class for session.load(...). But for specific parts I need access to specific fields of entities, so I have to cast object to precise type (B or C).

So, when I'm doing A a = (A) session.load(A.class, id); it constructs proxy object under type A, so it can not be cast to B or C:

java.lang.ClassCastException: my.A_$$_jvst551_6 cannot be cast to my.B

The question: is any way how I can configure my entities or use special tricks to load entity from database and obtain object of precise type of which correspondence row presents?

Answer 1

Well, it's easy: I should use session.get(A.class, id) instead of session.load(...).