you may often face the following exception in Hibernate.
java.lang.ClassCastException:
com.roshan.services.payment.gateway.domain.GatewayProfile_$$_javassist_11
This happens when you try to do something like this:
public void doSomething(IPaymentModeProfile paymentModeProfile){
//something goes here
switch (id) {
// ACH(101), CPA(102), CREDIT(103), DIRECT_DEBIT(104), MAESTRO(105),
// PINLESS_DEBIT(106)
case 101: {
//something goes here
}
break;
case 102: {
//something goes here
}
break;
case 103: {
CreditCard creditCard = (CreditCard) paymentModeProfile;
//do something with creditCard
}
break;
case 104: {
//something goes here
}
break;
case 105: {
//something goes here
}
break;
case 106: {
//something goes here
}
break;
}
}
Using interface proxies together with polymorphism can lead to sporadic ClassCastExceptions. This problem occurs whenever two mapped subclasses have an identical property and the instances are loaded polymorphically through the base class.
This was due to the fact that a lazily loaded List of objects retrieved by hibernate contained proxied objects. The entities that were proxied were using a single table inheritance strategy, so there is a base class that is subclassed several times. The entities once loaded were being sorted into separate lists that are typed according to the subclasses, they were being cast into the appropriate subclass but this cast was failing because instead of being an instance of say GatewayProfile it was an instance of GatewayProfile_$$_javassist_11 i.e.
Assume CreditCard implements the IPaymentModeProfile interface. The gist of the problem is that Hibernate is trying to optimize and avoid going to the database by returning a proxy object. However, a proxy object cannot be downcast to the subclass object, the exception occurs because of downcasting. There are lot of solution to avoid this problem.
The first solution to this issue is use their own interfaces instead of your entity and its subclass. In this case cglib creates a proxy class that implements all the interfaces specified in the proxy attribute (in both class and joined sub-class tags). Everywhere in your code, you should access the entity through the interfaces
and not the implementation classes.
Ex: create a Interface Called ICreditCard instead of CreditCard class.
Follow this link for more information.
http://sysin.wordpress.com/2009/02/27/hibernate-inheritance-classcastexception-part-1/
The second solution is that use visitor pattern.
Follow this link for more information.
http://andykayley.blogspot.com/2009/05/how-to-avoid-classcastexceptions-when.html
The third solution is extract the real object from hibernate proxy. This is very simple and not taking too much time to implement. This is the only solution that you don't need to write extra classes.
if (paymentModeProfile instanceof HibernateProxy) {
// convert the hibernate proxy to an object.
Object object = paymentModeProfile;
// get the real object
CreditCard creditCard = (CreditCard) ((HibernateProxy) object).getHibernateLazyInitializer().getImplementation();
// do anything with creditCard
}
cheers..!!!
