I have a hierarchy: User <-- Applicant <-- Member. I use table-per-class-hierarchy to implement this hierarchy of classes in my mapping file, user.hbm.xml.

At some point in my application, I change the type of User from Applicant to Member by callling , follow by some other initilization. This change and initialization are wrapped inside a transaction. My problem is that, after changing the discriminator value of Applicant, and flush it explicitly, I can't retrieve the object for type Member, which I want to use it to set member specific values. I know the fact that hibernate implements something called a transaction scope identify which causes this problem, but how do I fix this? I can solve it by changing the discriminator value in one transaction, and initialization in another, but I want them to be in one instead of two transactions.

Any advice is appreciated.

Did you try to evict the object from session and the attach it back?
session.evict( o );
and then
session.lock( o, ..);

wopsss, that works! Thank you!